Nonpapillary and papillary renal cell carcinoma: a cytogenetic and phenotypic study.

Cytogenetic and molecular genetic studies allow the common renal cell neoplasms to be separated into two main types: (1) Nonpapillary renal cell carcinomas (RCC) which have a loss of 3p13-pter sequences and (2) Papillary renal cell tumors having tri- or tetrasomies of chromosome 7 and trisomy 17. To investigate renal proximal (PT) and distal (DT) tubular epithelial phenotype expression in these genetically distinct neoplasms, a panel of antibodies and lectins selectively reactive with normal adult PT and DT was applied to 10 nonpapillary and seven papillary RCC. All tumors except one papillary RCC demonstrated characteristic karyotypes. Phenotype expression varied depending upon changes in the histopathologic patterns within a tumor. Among tumors composed of only one cell type, columnar, eosinophilic cells showed only PT staining and small, basophilic cells showed only DT staining. One tumor revealed a transition from small, basophilic cells to columnar, eosinophilic cells. The basophilic cells stained for DT markers and the eosinophilic cells for PT markers. One tumor consisted of nests of clear cells between indistinct papillary structures. The clear cells stained for both PT and DT markers. All 10 nonpapillary RCC demonstrated PT staining; nine exhibited DT markers. Staining was most intense in areas of tumor showing higher nuclear grades, tubuloglandular differentiation or in granular, eosinophilic cells and was absent or weak in solid groups of low nuclear grade clear cells. Papillary and nonpapillary RCC demonstrated lectin-binding or antigens associated with both PT and DT indicating a capacity for multipotential metanephric differentiation in each type of neoplasm.(ABSTRACT TRUNCATED AT 250 WORDS)