SERUM BIOMARKERS IN METASTATIC RENAL CELL CARCINOMA FRANCISCO H. DEXEUS, M.D. CHRISTOPHER J. LOGOTHETIS, M.D. AVISHAY SELLA, M.D. KAREN FITZ, R.N.

ANNE STRIEGEL, R.N., M.S.N. ROBERT J. AMATO, D.O. FRANK J. LIU, M.D.

From the Department of Medical Ontology and Division of Laboratory Medieine, The University of Texas M.D. Anderson Cancer Center, Houston, Texas

ABSTRACT--To identify possible clinically valuable markers of metastatic renal cell carcinoma, we measured the serum concentrations of several commercially available biomarkers in 117 patients with this disease. The alpha-/fetoprorein level was measured in 75 patients and was elevated in 8 (11%); elevation did not correlate with the presence o/f liver metastasis. Beta subunit of human chorionic gonadotropin levels increased in 8 of 83 patients tested (10 %). Cterminal parathyroid hormone levels were measured in 79 patients and were elevated in 15 (19 %); their serum creatinine level was normal. Thirteen of this group had normal serum calcium levels, whereas 7 patients with hypercalcemia and no clinically evident bone metastasis had normal parathyroid hormone levels. In only 2 of 72 patients, serum lactate dehydrogenase and its isoenzyme 1 were elevated. Only 1 of 85 patients had mildly elevated serum carcinoembryonic antigen, in contrast to 3 of 7 patients with metastatic transitional cell carcinoma of the renal pelvis who had moderately elevated carcinoembryonic antigen. Elevations in alpha-/fetoprotein, human chorionic gonadotropin, and parathyroid hormone correlated with the course of the disease in 13 patients/for whom ~follow-up measurements were available; measurement of these markers, however, is only useful in a small proportion of patients with metastatic renal cell carcinoma.

Although renal cell carcinomas are associated with a wide variety of paraneoplastic syndromes, no humoral factor or serum marker has been isolated consistently from patients with this disease. 1 In an effort to find some serum markers that could be clinically useful, we have measured the serum concentrations of five commercially available markers in patients with metastatic renal cell carcinomas. These included alpha-fetoprotein (AFP), beta subunit of the human chorionic gonadotropin (fl-HCG), lactic dehydrogenase (LD), and its isoenzymes

6

1 to 5, carcinoembryonic antigen (CEA), and, since hypercalcemia can occur in up to 15 percent of patients during the course of their disease, the C-terminal parathyroid hormone (CPTH). We have previously reported that patients with metastatic transitional cell carcinoma of the urothelium had a 17 percent incidence o f elevated CEA. 2 Therefore, we reviewed t h e records of 7 patients with metastatic transitional cell carcinoma of the renal pelvis, t o compare their CEA levels with those of the

UROLOGY

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VOLUME XXXVIII, NUMBER 1

~i~qurrent series of patients with metastatic renal ~ ! 1 carcinoma. ~i~:

Material and Methods

~

Between 1984 and 1988, we measured levels ~rcially available markers in the ttients who had metastatic renal and were enrolled in a variety of or immunotherapy protocols. ~asured by enzyme immunoassay atories, North Chicago, IL). Aemanufacturer, 97 percent of 338 :s had serum AFP values less than tsed on the levels in control subin our laboratory, we determined alues are 0 to 5 ng/mL, with an ficient of variation of 7 percent. [so measured by enzyme immu,tt Laboratories). Normal levels 1L, and the interassay coefficient 10 percent. Normal values were internal control assays. Those for l from less than 1.0 to 1.6 MIU/ emenopausal women, these were VlIU/mL; and for 2 of 15 post9men, they were 3.0 to 3.9 MIU/ ~, for women, ele;eations less than !~0 percent above the upper limit of the normal ~ n g e were defined as minimal, and elevations )~fS0 percent or more above the upper limit of : ~ e normal range were considered significant !)i" C-terminal PTH was measured by radioim'~i~unoassay in a reference commercial labora~ r y (Smith Kline/Bio-Science Laboratories, St. ~6uis, MO).3 The assay uses a synthesized flag~ n t of human PTH as the radiolabeled tracer. ~ e bound and free radiolabeled PTH are sepa! ~ t e d by a second antibody method. The assay i)~e~ndetect as little as 10 pg/mL PTH in an assay :!!f~be; in serum, the limit of detection is 50 pg/ :haL. The antiserum detects equally well the hub:man PTH fragment 37-84 (comprising the mid/~:dle and C-terminal regions) and the intact )i~uman PTH molecule 1-84. However, the anti~erum exhibits no reactivity with the N-term i n a l !-34 region of the hormone. In 130 nor:!~al subjects the PTH levels ranged from 50-399 pg/mL. The normal range, based in t h e mean + 9. standard deviations, is < 50-340 :~g/mL. Because of some evidence that PTH elevations may be caused by decreased glo~ e r u l a r filtration rates, 4 we correlated C-PTH 16vels with serum creatinine levels.

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Serum total LD e n z y m e activity was measured by a kinetic method of oxidating Llactate to pyruvate at 340 nm using a COBASBIO centrifugal analyzer (Roche Diagnostic Systems, Hoffmann La Roche Inc., Nutley, NJ). The reference range for serum total LD activity in our laboratory was 109 to 193 U/L. Serum LD isoenzyme separation was performed with the Paragon electrophoresis system, using the LD-isoenzyme electrophoresis kit (Beckman Instruments, Inc., Brea, CA). The reference ranges for the serum LD isoenzymes were LD1:19 percent to 30 percent, LD-2:32 percent to 48 percent, LD-3:12 percent to 22 percent, LD4:5 percent to 11 percent, and LD-5:5 percent to 13 percent. When the LD-1 isoenzyme is greater than 30 percent and the LD-1 isoenzyme in absolute units is greater than 58 U/L (30 % of 193 U/L), the LD-1 isoenzyme is considered to be elevated. CEA was measured by enzyme immunoassay (Abbott Laboratories). The normal level for nonsmokers is 0-3 ng/mL and for smokers, 0-6 ng/mL. Levels for control subjects (57 nonsmokers and 49 smokers) were analyzed in our laboratory. We found no values above 3.0 and 6.0 ng/mL, respectively.2 Pathologic data for all 117 patients were reviewed and confirmed in The University of Texas M.D. Anderson Cancer Center Pathology Department. All patients were enrolled in one of several chemotherapy or immunotherapy studies. The staging workup consisted of blood chemistry analyses, chest x-ray films, bone scans, bone x-ray films, and computed tomography scans of the abdomen. Results The elevated marker levels are summarized in Table I. Among the 75 patients whose AFP serum levels were measured, 8 (11%) had an elevation. There was no correlation between an elevated AFP level and the presence of liver metastasis as shown by computed tomography: only 3 of the 8 patients with elevated AFP levels had liver metastasis, whereas only 3 of the 11 patients with liver metastasis had elevated AFE Two patients with elevated AFP levels also had elevated alkaline phosphatase levels, but results of their other liver function tests were normal and bone metastasis was not clinically evident. In follow-up evaluations performed for 5 patients, the levels correlated with clinical course of disease (progressive in 4, stable in 1).

]'ABLE I.

Levels of elevated markers in patients with metastatic renal cell carcinoma

Marker AFT

Measured (No.) 75

Elevated No. ( % ) 8 (11)

Mean Elevation 140 + 194 ng/mL

fl-HCG

83

10 (12)

C-PTH

79

15 ( 1 9 )

LDH

72

2 (3)

3,250 MIU/ML

CEA

85

1 (1)

7.5 ng/mL

14.1 + 20.5 MIU/mL 683.6 _+ 386.8 pg/mL

Median Elevation (Range) 49 ng/mL (9.5-531 ng/mL) 5.8 MIU/mL (3.5-69.7 MIU/mL) 541 pg/mL (365-1,638 pg/mL) 3,250 MIU/mL (2,883-3,617 MIU/mL) 7.5 ng/mL

Normal Values < 5 ng/mL < 3 MIU/mL < 340 pg/mL < 193 MIU/mL < 6 ng/mL

KEY: AFP, alpha fetoprotein; fl-HCG, beta subunit of human chorionic gonadotropin; C-PTH, C-terminal parathyroid hormone; LDH, lactate dehydrogenase; CEA, eareinoembryonie antigen.

fl-HCG levels were measured in 83 patients. Nine postmenopausal w o m e n had elevations of less than 50 percent above the upper limit of the normal range, which were not considered significant. Levels in 10 patients (12%), 4 men and 6 women, were significant (Table I). Follow-up levels were determined for 4 patients and correlated with the course of the disease (2 responding, 1 progressing, and 1 stable). Twenty-six (33 %) of the 79 patients evaluated for C-PTH had serum levels above the normal range. However, 11 of these also had elevated serum creatinine levels (the normal level established in our laboratory is < 1 . 5 mg/100 m L for m e n , a n d -

Serum biomarkers in metastatic renal cell carcinoma.

To identify possible clinically valuable markers of metastatic renal cell carcinoma, we measured the serum concentrations of several commercially avai...
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