GENETICS AS A DIAGNOSTIC-TOOL IN SARCOMATOID RENAL-CELL CANCER

Renal-cell cancer comprises a heterogeneous group of tumors, which cur rently can be sub-divided into morphologically distinct entities, each characterized by a specific combination of genetic changes. Sarcomato id transformation might occur in any of the sub-types, resulting in tu mors consisting of both carcinomatous and sarcomatous components. The specific diagnosis of these neoplasms, as to tumor sub-type, is usuall y made on the histologic properties of the carcinomatous tissue presen t. However, this might not reflect the true nature of the sarcomatous component. Since the genetic changes associated with the development o f the different sub-types of renal-cell cancer are well established, t his knowledge might serve as a tool in diagnosing sarcomatoid tumors. Assessing the genetic constitution of the latter may lead to correct d iagnosis, It may also provide valuable information about the genetic c hanges associated with sarcomatoid transformation. Hence we performed a genetic characterization of a case of sarcomatoid renal cell cancer, histologically diagnosed as being of the chromophilic type. The obser ved genetic changes included loss of 3p, 6q, 8p, 9, 13, 14 and 17p, an d gain of 5, 12 and 20, as well as a mutation in the coding region of the p53 gene. This combination of genetic changes points to clear-cell rather than chromophilic origin of the sarcomatoid tumor investigated , indicating that the genetic constitution of sarcomatoid tumors may b e a more reliable indicator of tumor sub-type than histologic appearan ce. (C) 1997 Wiley-Liss, Inc.