Clin Oral Invest DOI 10.1007/s00784-015-1472-x
ORIGINAL ARTICLE
Salivary and serum leptin levels in patients with squamous cell carcinoma of the buccal mucosa Jasdeep Kaur 1,2 & Reinhilde Jacobs 1,2
Received: 29 January 2014 / Accepted: 5 April 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Objectives Leptin levels are associated with appetite and energy expenditure in healthy individuals. The present study aims to evaluate serum and salivary leptin concentrations in patients with squamous cell carcinoma of the buccal mucosa. Materials and methods Enrolled participants in this study included 41 patients with squamous cell carcinoma of the buccal mucosa and 40 healthy control patients. Serum leptin levels were measured via enzyme-linked immunosorbent assay (ELISA) method in all subjects and reported in units of nanograms per millilitre. Salivary leptin levels were measured by a highly sensitive and specific non-equilibrium version of a dedicated custom radioimmunoassay. Results A significant reduction in salivary and serum leptin levels in patients with squamous cell carcinoma of the buccal mucosa was observed in comparison to control subjects. In addition, a significant correlation was shown between serum and salivary leptin levels on one hand and body mass index, with various histopathological and TNM (tumour nodes metastasis) staging variants of squamous cell carcinoma of the buccal mucosa on another. A highly significant correlation was shown between salivary and serum leptin levels in both groups.
* Jasdeep Kaur [email protected] 1
OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven, Leuven, Belgium
2
Oral and Maxillo-facial Surgery, University Hospitals Leuven, Leuven, Belgium
Conclusion The results of this study demonstrate a possible mechanism of salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa. Clinical relevance Salivary leptin might play a role in squamous cell carcinoma of the buccal mucosa. Keywords Squamous cell carcinoma of the buccal mucosa . Salivary . Serum . Leptin . Cachexia
Introduction Oral squamous cell carcinoma (OSC) is the most common head and neck malignancy. As the sixth most common cancer in the world, it is a solemn public health problem. Early detection of OSC is essential to achieve better patient outcomes. It has been reported that half of the cancer patients are affected by cachexia—characterized by anorexia, loss of adipose tissue and deterioration of skeletal muscles, contributing significantly to mortality [1]. Cachexia is more common in children and elderly patients and becomes more pronounced as the disease progresses. The prevalence of cachexia increases from 50 % to more than 80 % before death. It is the main cause of death in 20 % of the patients [2]. Cachexia occurs secondarily as a result of a functional inability to ingest or use nutrients. This may be related to mechanical interference in the gastrointestinal tract caused by obstruction or malabsorption, surgical interventions or treatment-related toxicity, in patients receiving chemotherapy. Consequent nausea, vomiting, taste changes, stomatitis and diarrhoea can contribute to weight loss [3]. Several causative agents such as cytokines, circulating hormones, neuropeptides, neurotransmitters and tumour-derived factors have been proposed
Clin Oral Invest
[4–9]. An emerging view is that the anorexia in cachexia is mainly caused by cytokines produced by the tumour mass or by the immune system in response to the presence of the malignancy that in turn induces profound lypolysis and protein degradation [1]. Leptin, a hormone secreted by adipose tissue, is now known to be an integral component of the homeostatic loop of body weight regulation [1–5]. Low leptin levels in the brain increase the activity of the hypothalamic orexigenic signals that stimulate feeding, suppress energy expenditure and decrease the activity of anorexigenic signals that suppress appetite and increase energy expenditure [6, 7]. Most of the orexigenic signals are known to be up-regulated through fasting in experimental animals. This suggests that these signals play an important role in facilitating the recovery of lost weight. Cancer-induced anorexia may result from circulating factors produced by the tumour or by the host in its response. Several cytokines have been proposed as mediators of the cachectic process, including tumour necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6) and interferon-γ (IFN-γ) [8]. High serum levels of TNF-α, IL-1 and IL-6 have been found in some cancer patients, and the levels of these cytokines seem to correlate with the progression of the tumours. Chronic administration of these cytokines, either alone or in combination, is capable of reducing food intake and reproducing the distinct features of the cancer anorexia-cachexia syndrome [9]. These cytokines may produce long-term inhibition of feeding by stimulating the expression and release of leptin and/or by mimicking the hypothalamic effect of excessive negative feedback signalling from leptin, leading to the prevention of the normal compensatory mechanisms in the face of both decreased food intake and body weight. Various studies have reported that there is a decrease in serum leptin in cancer patients compared to controls [10], but only one study has reported on serum leptin levels in oral squamous cell carcinoma patients. A significant reduction in leptin levels was observed in oral squamous cell carcinoma patients [11]. Squamous cell carcinoma of the buccal mucosa is highly prevalent in northern parts of India, but no studies have been published on the Indian population looking at salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa. The aim of our study therefore was to assess salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa and to compare levels to those in normal healthy controls. In addition, we looked to correlate leptin levels to factors such as histopathological grading, weight loss, TNM (tumour nodes metastasis) staging of the tumour, and body mass index (BMI).
Materials and methods Subjects The forty-one patients (20:21; M:F) with histopathological confirmation of squamous cell carcinoma of the buccal mucosa and 40 normal subjects (20:20; M:F) without any systemic disease aged 40–65 years from the northern part of India were selected after obtaining informed consent. All patients were staged by TNM classification [12]. Patients with a history of chemotherapy, radiotherapy, oncological surgery, malignancy, obesity, systemic diseases, bronchial asthma, drug allergies, as well as alcoholics, smokers, and tobacco chewers were excluded from the study. Different parameters were studied as shown in Table 1. BMI of each individual was calculated using the following formula: BMI=m/l2 (kg/m2), m=mass in kg and l=height in m [13]. Body weight was measured at least 7 months before the study, as baseline data. The pecentage loss of weight was calculated after obtaining baseline and actual values. This study was approved by the ethical committee of Baba Nidhan Singh Hospital, Punjab, India. Procedure Samples of approximately 5 ml of blood were drawn from fasting patients under aseptic precautions. The samples were then centrifuged for 5 min to obtain serum and stored at −65 °C in sterile vials. During the examination, paraffin wax stimulated whole saliva secretion. These samples were collected and stored at −20 °C until analysis. The saliva samples were centrifuged at 8,000g for 9 min. They were then frozen immediately and stored at −25 °C until measurement. Serum leptin levels were quantified using a double antibody radioimmunoassay (Linco Res., St. Louis, MO, USA). Intra-batch coefficients of variation were between 3 and 5 %, and the inter-assay coefficient of variation was between 6 and 12 %. To measure salivary leptin, a highly sensitive and specific non-equilibrium version of an in-house radioimmunoassay was used [13, 14]. The sensitivity (accuracy) of this Table 1
Parameters studied in the patients and control group
Sr. no.
Parameters
1. 2. 3. 4. 5. 6. 7.
BMI TNM staging Age and demographical parameters Salivary leptin Serum leptin Histopathology Weight loss (%)
Clin Oral Invest Table 2
Mean (SD) of BMI, weight loss (%) and serum and salivary leptin levels in the patients and control group (ANOVA)
Parameters
Control group (n=41)
Study group (n=40)
P
Range and mean (SD) age (years)
BMI (kg/m2)
26.46 (3.48)
46–60 42.67 (16.02) 3.54 (1.77) Male=3.03 (1.08) Female=4.92 (2.12) 60 (21) Male=55 (23) Female=65 (20) Female=8.9 (2.3) Male=7.5 (2.6) 17.52 (3.23)
0.578
Weight loss (kg)
45–60 46.45 (10.45) 6.03 (2.76) Male=5.06 (2.34) Female=7.78 (2.72) 180 (101) Male=178 (89) Female=189 (100) –
Serum leptin (ng/ml)
Salivary leptin (pg/ml)
modification was 2 pg/ml. Inter-assay and intra-assay coefficients of variation were 15.2 and 9.1 %, respectively. Statistical analysis The Student t test was used for comparing salivary and serum leptin levels in controls and patients with squamous cell carcinoma of the buccal mucosa. Gender effects and the influence of age and BMI were checked as well. Furthermore, analysis of variance (ANOVA) was used to compare salivary and serum leptin levels and BMI in various histopathological gradings and TNM stagings. Mean BMI, leptin and mean serum and salivary leptin levels of both of the groups were correlated using Pearson’s correlation. Correlation between BMI and serum and salivary leptin levels for each histopathological grading and TNM stage was also performed.
Results A significant reduction in salivary and serum leptin levels in patients with squamous cell carcinoma of the buccal mucosa was observed when compared to controls (Table 2). When analysing the Pearson correlation values, it was observed that salivary and serum leptin levels showed a significant correlation with weight loss in both groups (Table 3). It was however Table 3
0.0001
0.0001
0.00001
found that weight loss and BMI was highly correlated with serum leptin as compared to salivary leptin. Mean salivary and serum leptin levels were compared with various histopathological gradings (Table 3), and significant differences were observed between the mean serum leptin levels of welldifferentiated and moderately differentiated squamous cell carcinoma of the buccal mucosa. Mean weight loss was significantly related to both histological tumour grading and TNM staging.
Discussion The primary aim of the present study was to evaluate the serum and salivary leptin levels in patients with squamous cell carcinoma of the buccal mucosa, and we conclusively demonstrate that salivary and serum leptin levels are significantly decreased in the cancer group when compared to the control group, a finding which is supported by previous studies on cancer patients [16, 17]. We postulate that low serum leptin levels might be related to decreased body fat mass in cancer patients [15]. Weight loss was detected in our cancer patients. Consequently, a decrease in leptin concentration may possibly be related to a decrease in body fat mass, which develops secondarily to weight loss in cancer patients. Healthy women have more adipose tissue and therefore have higher leptin
Mean serum and salivary leptin levels and weight loss in different histological gradings
Histological variants
Mean serum leptin (ng/ml)
Mean salivary leptin (pg/ml)
Weight loss percentage (%)
Salivary and serum leptin levels and histopathological (r, P)
Weight loss and histopathological (r, P)
Well-differentiated oral squamous cell carcinoma Moderately differentiated oral squamous cell carcinoma Poorly differentiated oral squamous cell carcinoma
2.98 (1.85)
54 (35)
7.3 (3.4)
0.86, 0.007
0.73, 0.001
3.54 (2.45)
65 (23)
7.8 (3.1)
0.78, 0.005
0.74, 0.004
3.84 (1.45)
67 (24)
8.6 (4.1)
0.45, 0.879
0.67, 0.001
Clin Oral Invest
concentrations than men with equivalent BMI [15]. Similarly, we have shown that serum and salivary leptin concentrations are higher in women in contrast to men in controls. Furthermore, higher levels of serum and salivary leptin levels were observed in poorly differentiated as compared to welldifferentiated oral squamous cell carcinoma. This might be due to leptin and leptin receptor dysreulation in cancer cells [18]. Leptin signalling leads to the metabolic features associated with cancer malignancy, such as switching the cell energy balance from mitochondrial β-oxidation to the aerobic glycolytic pathway. Leptin rapidly induces the activation of JAK2, STAT3 and MAPK (ERK1/2) signalling cascades; it may also induce HER2 transactivation via leptin-induced phosphoJAK2 [19, 20]. Leptin provides the tumour microenvironment, mainly through its ability to potentiate both migration of endothelial cells and angiogenesis and to sustain the recruitment of macrophages and monocytes, which in turn secrete vascular endothelial growth factor and proinflammatory cytokines [21]. In this study, a positive correlation between leptin and BMI is observed in well-differentiated and moderately differentiated squamous cell carcinoma of the buccal mucosa, which may indicate an increased leptin activity in the tumour mass in relation to the cytokines inducing anorexia [3]. Significant differences were observed in salivary and serum leptin levels, BMI and various TNM stagings of tumour. This may be explained by an enhanced production of cytokines which develops negative feedback signals from leptin on the hypothalamus [5]. The results of this study establish a possible mechanism of salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa.
References 1. 2. 3.
4. 5.
6.
7. 8.
9. 10.
11. 12. 13.
14.
15.
Conclusion 16.
The results of this study conclude a possible mechanism of salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa.
17. 18.
Clinical relevance
19.
Salivary leptin might play a role in squamous cell carcinoma of the buccal mucosa.
20.
21. Conflict of interest No confict of interest
Inui A (1999) Cancer anorexia-cachexia syndrome: are neuropeptides the key? Cancer Res 59:4493–44501 Bruera E (1977) Anorexia, cachexia and nutrition. Br Med J 315: 1219–1222 Billingsley KG, Alexander HR (1996) The pathophysiology of cachexia in advanced cancer and AIDS. In: Bruera E, Higginson I (eds) Cachexia-anorexia in cancer patients. Oxford University Press, Oxford, pp 1–22 Friedman JM, Halaas JL (1998) Leptin and the regulation of body weight in mammals. Nature 395:763–770 Elmquist JK, Maratos-Flier E, Saper CB et al (1998) Unraveling the central nervous system pathways underlying responses to leptin. Nat Neurosci 1:445–450 Inui A (1999) Feeding and body-weight regulation by hypothalamic neuropeptides-mediation of the actions of leptin. Trends Neurosci 22:62–67 Schwartz MW, Seeley RJ (1997) Neuroendocrine responses to starvation and weight loss. N Engl J Med 336:1802–1811 Moldawer LL, Copeland EM (1997) Proinflammatory cytokines, nutritional support, and the cachexia syndrome: interactions and therapeutic options. Cancer 79:1828–1839 Noguchi Y, Yoshikawa T, Matsumoto A et al (1996) Are cytokines possible mediators of cancer cachexia? Surg Today 26:467–475 Bolukbas FF, Kilik H, Bolukbas C et al (2004) Serum leptin concentration and advanced gastrointestinal cancer: a case controlled study. BMC Cancer 4:29 Gharote HP, Mody RN (2009) Estimation of serum leptin in oral squamous cell carcinoma. J Oral Pathol Med 39:69–73 International Union Against Cancer (1997) TNM classification of malignant tumours, 5th edn. Wiley-Liss, New York Expert Consultation WHO (2004) Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 363:157–163 Gröschl M, Wagner R, Dörr HG, Blum WF, Rascher W, Dötsch J et al (2000) Variability of leptin values measured from different sample matrices. Horm Res 54:26–31 Wallace AM, Sattar N, McMillan DC (1998) Effect of weight loss and the inflammatory response on leptin concentrations in gastrointestinal cancer patients. Clin Cancer Res 4:2977–2979 Tessitore L, Vizio B, Jenkins O, De Stefano I, Ritossa C, Argiles JM, Benedetto C, Mussa A et al (2000) Leptin expression in colorectal and breast cancer patients. Int J Mol Med 5:421–426 Somsundar P, McFedden DW, Hileman SM, Vona-Davis L (2004) Leptin is a growth factor in cancer. J Surg Res 116:337–349 Uddin S, Hussain AR, Siraj AK, Khan OS, Bavi PP, Al-Kuraya KS et al (2011) Role of leptin and its receptors in the pathogenesis of thyroid cancer. Int J Clin Exp Pathol 4:637–643 Samuel-Mendelsohn S, Inbar M, Weiss-Messer E, Niv-Spector L, Gertler A, Barkey RJ et al (2011) Leptin signaling and apoptotic effects in human prostate cancer cell lines. Prostate 71:929–945 Giordano C, Vizza D, Panza S, Barone I, Bonofiglio D, Lanzino M, Sisci D, De Amicis F, Fuqua SA, Catalano S, Andò S (2013) Leptin increases HER2 protein levels through a STAT3-mediated up-regulation of Hsp90 in breast cancer cells. Mol Oncol 7:379–391 Andò S, Catalano S (2011) The multifactorial role of leptin in driving the breast cancer microenvironment. Nat Rev Endocrinol 8: 263–275
ORIGINAL ARTICLE
Salivary and serum leptin levels in patients with squamous cell carcinoma of the buccal mucosa Jasdeep Kaur 1,2 & Reinhilde Jacobs 1,2
Received: 29 January 2014 / Accepted: 5 April 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Objectives Leptin levels are associated with appetite and energy expenditure in healthy individuals. The present study aims to evaluate serum and salivary leptin concentrations in patients with squamous cell carcinoma of the buccal mucosa. Materials and methods Enrolled participants in this study included 41 patients with squamous cell carcinoma of the buccal mucosa and 40 healthy control patients. Serum leptin levels were measured via enzyme-linked immunosorbent assay (ELISA) method in all subjects and reported in units of nanograms per millilitre. Salivary leptin levels were measured by a highly sensitive and specific non-equilibrium version of a dedicated custom radioimmunoassay. Results A significant reduction in salivary and serum leptin levels in patients with squamous cell carcinoma of the buccal mucosa was observed in comparison to control subjects. In addition, a significant correlation was shown between serum and salivary leptin levels on one hand and body mass index, with various histopathological and TNM (tumour nodes metastasis) staging variants of squamous cell carcinoma of the buccal mucosa on another. A highly significant correlation was shown between salivary and serum leptin levels in both groups.
* Jasdeep Kaur [email protected] 1
OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven, Leuven, Belgium
2
Oral and Maxillo-facial Surgery, University Hospitals Leuven, Leuven, Belgium
Conclusion The results of this study demonstrate a possible mechanism of salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa. Clinical relevance Salivary leptin might play a role in squamous cell carcinoma of the buccal mucosa. Keywords Squamous cell carcinoma of the buccal mucosa . Salivary . Serum . Leptin . Cachexia
Introduction Oral squamous cell carcinoma (OSC) is the most common head and neck malignancy. As the sixth most common cancer in the world, it is a solemn public health problem. Early detection of OSC is essential to achieve better patient outcomes. It has been reported that half of the cancer patients are affected by cachexia—characterized by anorexia, loss of adipose tissue and deterioration of skeletal muscles, contributing significantly to mortality [1]. Cachexia is more common in children and elderly patients and becomes more pronounced as the disease progresses. The prevalence of cachexia increases from 50 % to more than 80 % before death. It is the main cause of death in 20 % of the patients [2]. Cachexia occurs secondarily as a result of a functional inability to ingest or use nutrients. This may be related to mechanical interference in the gastrointestinal tract caused by obstruction or malabsorption, surgical interventions or treatment-related toxicity, in patients receiving chemotherapy. Consequent nausea, vomiting, taste changes, stomatitis and diarrhoea can contribute to weight loss [3]. Several causative agents such as cytokines, circulating hormones, neuropeptides, neurotransmitters and tumour-derived factors have been proposed
Clin Oral Invest
[4–9]. An emerging view is that the anorexia in cachexia is mainly caused by cytokines produced by the tumour mass or by the immune system in response to the presence of the malignancy that in turn induces profound lypolysis and protein degradation [1]. Leptin, a hormone secreted by adipose tissue, is now known to be an integral component of the homeostatic loop of body weight regulation [1–5]. Low leptin levels in the brain increase the activity of the hypothalamic orexigenic signals that stimulate feeding, suppress energy expenditure and decrease the activity of anorexigenic signals that suppress appetite and increase energy expenditure [6, 7]. Most of the orexigenic signals are known to be up-regulated through fasting in experimental animals. This suggests that these signals play an important role in facilitating the recovery of lost weight. Cancer-induced anorexia may result from circulating factors produced by the tumour or by the host in its response. Several cytokines have been proposed as mediators of the cachectic process, including tumour necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6) and interferon-γ (IFN-γ) [8]. High serum levels of TNF-α, IL-1 and IL-6 have been found in some cancer patients, and the levels of these cytokines seem to correlate with the progression of the tumours. Chronic administration of these cytokines, either alone or in combination, is capable of reducing food intake and reproducing the distinct features of the cancer anorexia-cachexia syndrome [9]. These cytokines may produce long-term inhibition of feeding by stimulating the expression and release of leptin and/or by mimicking the hypothalamic effect of excessive negative feedback signalling from leptin, leading to the prevention of the normal compensatory mechanisms in the face of both decreased food intake and body weight. Various studies have reported that there is a decrease in serum leptin in cancer patients compared to controls [10], but only one study has reported on serum leptin levels in oral squamous cell carcinoma patients. A significant reduction in leptin levels was observed in oral squamous cell carcinoma patients [11]. Squamous cell carcinoma of the buccal mucosa is highly prevalent in northern parts of India, but no studies have been published on the Indian population looking at salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa. The aim of our study therefore was to assess salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa and to compare levels to those in normal healthy controls. In addition, we looked to correlate leptin levels to factors such as histopathological grading, weight loss, TNM (tumour nodes metastasis) staging of the tumour, and body mass index (BMI).
Materials and methods Subjects The forty-one patients (20:21; M:F) with histopathological confirmation of squamous cell carcinoma of the buccal mucosa and 40 normal subjects (20:20; M:F) without any systemic disease aged 40–65 years from the northern part of India were selected after obtaining informed consent. All patients were staged by TNM classification [12]. Patients with a history of chemotherapy, radiotherapy, oncological surgery, malignancy, obesity, systemic diseases, bronchial asthma, drug allergies, as well as alcoholics, smokers, and tobacco chewers were excluded from the study. Different parameters were studied as shown in Table 1. BMI of each individual was calculated using the following formula: BMI=m/l2 (kg/m2), m=mass in kg and l=height in m [13]. Body weight was measured at least 7 months before the study, as baseline data. The pecentage loss of weight was calculated after obtaining baseline and actual values. This study was approved by the ethical committee of Baba Nidhan Singh Hospital, Punjab, India. Procedure Samples of approximately 5 ml of blood were drawn from fasting patients under aseptic precautions. The samples were then centrifuged for 5 min to obtain serum and stored at −65 °C in sterile vials. During the examination, paraffin wax stimulated whole saliva secretion. These samples were collected and stored at −20 °C until analysis. The saliva samples were centrifuged at 8,000g for 9 min. They were then frozen immediately and stored at −25 °C until measurement. Serum leptin levels were quantified using a double antibody radioimmunoassay (Linco Res., St. Louis, MO, USA). Intra-batch coefficients of variation were between 3 and 5 %, and the inter-assay coefficient of variation was between 6 and 12 %. To measure salivary leptin, a highly sensitive and specific non-equilibrium version of an in-house radioimmunoassay was used [13, 14]. The sensitivity (accuracy) of this Table 1
Parameters studied in the patients and control group
Sr. no.
Parameters
1. 2. 3. 4. 5. 6. 7.
BMI TNM staging Age and demographical parameters Salivary leptin Serum leptin Histopathology Weight loss (%)
Clin Oral Invest Table 2
Mean (SD) of BMI, weight loss (%) and serum and salivary leptin levels in the patients and control group (ANOVA)
Parameters
Control group (n=41)
Study group (n=40)
P
Range and mean (SD) age (years)
BMI (kg/m2)
26.46 (3.48)
46–60 42.67 (16.02) 3.54 (1.77) Male=3.03 (1.08) Female=4.92 (2.12) 60 (21) Male=55 (23) Female=65 (20) Female=8.9 (2.3) Male=7.5 (2.6) 17.52 (3.23)
0.578
Weight loss (kg)
45–60 46.45 (10.45) 6.03 (2.76) Male=5.06 (2.34) Female=7.78 (2.72) 180 (101) Male=178 (89) Female=189 (100) –
Serum leptin (ng/ml)
Salivary leptin (pg/ml)
modification was 2 pg/ml. Inter-assay and intra-assay coefficients of variation were 15.2 and 9.1 %, respectively. Statistical analysis The Student t test was used for comparing salivary and serum leptin levels in controls and patients with squamous cell carcinoma of the buccal mucosa. Gender effects and the influence of age and BMI were checked as well. Furthermore, analysis of variance (ANOVA) was used to compare salivary and serum leptin levels and BMI in various histopathological gradings and TNM stagings. Mean BMI, leptin and mean serum and salivary leptin levels of both of the groups were correlated using Pearson’s correlation. Correlation between BMI and serum and salivary leptin levels for each histopathological grading and TNM stage was also performed.
Results A significant reduction in salivary and serum leptin levels in patients with squamous cell carcinoma of the buccal mucosa was observed when compared to controls (Table 2). When analysing the Pearson correlation values, it was observed that salivary and serum leptin levels showed a significant correlation with weight loss in both groups (Table 3). It was however Table 3
0.0001
0.0001
0.00001
found that weight loss and BMI was highly correlated with serum leptin as compared to salivary leptin. Mean salivary and serum leptin levels were compared with various histopathological gradings (Table 3), and significant differences were observed between the mean serum leptin levels of welldifferentiated and moderately differentiated squamous cell carcinoma of the buccal mucosa. Mean weight loss was significantly related to both histological tumour grading and TNM staging.
Discussion The primary aim of the present study was to evaluate the serum and salivary leptin levels in patients with squamous cell carcinoma of the buccal mucosa, and we conclusively demonstrate that salivary and serum leptin levels are significantly decreased in the cancer group when compared to the control group, a finding which is supported by previous studies on cancer patients [16, 17]. We postulate that low serum leptin levels might be related to decreased body fat mass in cancer patients [15]. Weight loss was detected in our cancer patients. Consequently, a decrease in leptin concentration may possibly be related to a decrease in body fat mass, which develops secondarily to weight loss in cancer patients. Healthy women have more adipose tissue and therefore have higher leptin
Mean serum and salivary leptin levels and weight loss in different histological gradings
Histological variants
Mean serum leptin (ng/ml)
Mean salivary leptin (pg/ml)
Weight loss percentage (%)
Salivary and serum leptin levels and histopathological (r, P)
Weight loss and histopathological (r, P)
Well-differentiated oral squamous cell carcinoma Moderately differentiated oral squamous cell carcinoma Poorly differentiated oral squamous cell carcinoma
2.98 (1.85)
54 (35)
7.3 (3.4)
0.86, 0.007
0.73, 0.001
3.54 (2.45)
65 (23)
7.8 (3.1)
0.78, 0.005
0.74, 0.004
3.84 (1.45)
67 (24)
8.6 (4.1)
0.45, 0.879
0.67, 0.001
Clin Oral Invest
concentrations than men with equivalent BMI [15]. Similarly, we have shown that serum and salivary leptin concentrations are higher in women in contrast to men in controls. Furthermore, higher levels of serum and salivary leptin levels were observed in poorly differentiated as compared to welldifferentiated oral squamous cell carcinoma. This might be due to leptin and leptin receptor dysreulation in cancer cells [18]. Leptin signalling leads to the metabolic features associated with cancer malignancy, such as switching the cell energy balance from mitochondrial β-oxidation to the aerobic glycolytic pathway. Leptin rapidly induces the activation of JAK2, STAT3 and MAPK (ERK1/2) signalling cascades; it may also induce HER2 transactivation via leptin-induced phosphoJAK2 [19, 20]. Leptin provides the tumour microenvironment, mainly through its ability to potentiate both migration of endothelial cells and angiogenesis and to sustain the recruitment of macrophages and monocytes, which in turn secrete vascular endothelial growth factor and proinflammatory cytokines [21]. In this study, a positive correlation between leptin and BMI is observed in well-differentiated and moderately differentiated squamous cell carcinoma of the buccal mucosa, which may indicate an increased leptin activity in the tumour mass in relation to the cytokines inducing anorexia [3]. Significant differences were observed in salivary and serum leptin levels, BMI and various TNM stagings of tumour. This may be explained by an enhanced production of cytokines which develops negative feedback signals from leptin on the hypothalamus [5]. The results of this study establish a possible mechanism of salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa.
References 1. 2. 3.
4. 5.
6.
7. 8.
9. 10.
11. 12. 13.
14.
15.
Conclusion 16.
The results of this study conclude a possible mechanism of salivary and serum leptin levels in squamous cell carcinoma of the buccal mucosa.
17. 18.
Clinical relevance
19.
Salivary leptin might play a role in squamous cell carcinoma of the buccal mucosa.
20.
21. Conflict of interest No confict of interest
Inui A (1999) Cancer anorexia-cachexia syndrome: are neuropeptides the key? Cancer Res 59:4493–44501 Bruera E (1977) Anorexia, cachexia and nutrition. Br Med J 315: 1219–1222 Billingsley KG, Alexander HR (1996) The pathophysiology of cachexia in advanced cancer and AIDS. In: Bruera E, Higginson I (eds) Cachexia-anorexia in cancer patients. Oxford University Press, Oxford, pp 1–22 Friedman JM, Halaas JL (1998) Leptin and the regulation of body weight in mammals. Nature 395:763–770 Elmquist JK, Maratos-Flier E, Saper CB et al (1998) Unraveling the central nervous system pathways underlying responses to leptin. Nat Neurosci 1:445–450 Inui A (1999) Feeding and body-weight regulation by hypothalamic neuropeptides-mediation of the actions of leptin. Trends Neurosci 22:62–67 Schwartz MW, Seeley RJ (1997) Neuroendocrine responses to starvation and weight loss. N Engl J Med 336:1802–1811 Moldawer LL, Copeland EM (1997) Proinflammatory cytokines, nutritional support, and the cachexia syndrome: interactions and therapeutic options. Cancer 79:1828–1839 Noguchi Y, Yoshikawa T, Matsumoto A et al (1996) Are cytokines possible mediators of cancer cachexia? Surg Today 26:467–475 Bolukbas FF, Kilik H, Bolukbas C et al (2004) Serum leptin concentration and advanced gastrointestinal cancer: a case controlled study. BMC Cancer 4:29 Gharote HP, Mody RN (2009) Estimation of serum leptin in oral squamous cell carcinoma. J Oral Pathol Med 39:69–73 International Union Against Cancer (1997) TNM classification of malignant tumours, 5th edn. Wiley-Liss, New York Expert Consultation WHO (2004) Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 363:157–163 Gröschl M, Wagner R, Dörr HG, Blum WF, Rascher W, Dötsch J et al (2000) Variability of leptin values measured from different sample matrices. Horm Res 54:26–31 Wallace AM, Sattar N, McMillan DC (1998) Effect of weight loss and the inflammatory response on leptin concentrations in gastrointestinal cancer patients. Clin Cancer Res 4:2977–2979 Tessitore L, Vizio B, Jenkins O, De Stefano I, Ritossa C, Argiles JM, Benedetto C, Mussa A et al (2000) Leptin expression in colorectal and breast cancer patients. Int J Mol Med 5:421–426 Somsundar P, McFedden DW, Hileman SM, Vona-Davis L (2004) Leptin is a growth factor in cancer. J Surg Res 116:337–349 Uddin S, Hussain AR, Siraj AK, Khan OS, Bavi PP, Al-Kuraya KS et al (2011) Role of leptin and its receptors in the pathogenesis of thyroid cancer. Int J Clin Exp Pathol 4:637–643 Samuel-Mendelsohn S, Inbar M, Weiss-Messer E, Niv-Spector L, Gertler A, Barkey RJ et al (2011) Leptin signaling and apoptotic effects in human prostate cancer cell lines. Prostate 71:929–945 Giordano C, Vizza D, Panza S, Barone I, Bonofiglio D, Lanzino M, Sisci D, De Amicis F, Fuqua SA, Catalano S, Andò S (2013) Leptin increases HER2 protein levels through a STAT3-mediated up-regulation of Hsp90 in breast cancer cells. Mol Oncol 7:379–391 Andò S, Catalano S (2011) The multifactorial role of leptin in driving the breast cancer microenvironment. Nat Rev Endocrinol 8: 263–275
