METALLOTHIONEIN EXPRESSION IN RENAL-CANCER

Objectives. To assess metallothionein (MT) expression with immunohisto chemical localization in human renal cell carcinoma and to determine w hether a possible relationship with the histopathologic findings, tumo r grade, or pathologic tumor stage is demonstrable, because MT may hav e a role in carcinogenesis. Methods. Archival pathologic specimens and medical records were reviewed for 28 patients with renal cell carcino ma. Immunohistochemical localization of MT was performed with a polycl onal-antibody-to-rat-liver MT, an anti-rabbit Ige linking antibody, an d an avidin-biotin horseradish peroxidase complex. Correlation was sou ght between immunohistochemical data (MT staining intensity, extension , and subcellular site) and clinical data (histologic cell type, tumor grade, and pathologic stage). Results. The mean patient age was 61.7 years (range 42 to 86). The predominant histologic cell type was the c lear cell variant. Three, sixteen, and nine tumors were pathologically staged as 1, 2, and 3, respectively. There were 1, 13, 10, and 4 tumo rs with grades 1, 2, 3, and 4, respectively. Among the independent var iables, greater immunoreactivity was observed in Stage 2 tumors (P = 0 .028). A significant inverse relationship between tumor grade and MT s taining intensity was also observed (P = 0.007). Conclusions. The inve rse relationship in renal cell carcinoma between MT immunoreactivity a nd tumor grade may indicate a role for MT in tumor growth and dediffer entiation. Increased MT immunoreactivity in lower stage tumors may be related to rapid tumor growth during their growth cycle. Further study is required to elucidate the role of MT in renal cell carcinoma oncog enesis and its possible use as a clinical prognostic parameter. (C) 19 98, Elsevier Science Inc. All rights reserved.