DETECTION OF P53 GENE ALTERATION IN RENAL-CELL CANCER BY MICROPREPARATION TECHNIQUES OF TUMOR SPECIMENS

Alterations in the p53 tumor-suppressor gene have been identified in a variety of human malignancies, including renal-cell cancer. A techniq ue for the isolation of tumor areas from tissue specimens to analyze f ormalin-fixed and paraffin-embedded tumors and try to avoid a disturba nce of the results due to genetic background signal by the presence of tumorinfiltrating lymphocytes, was established. The presence of lymph ocytes within the tumor areas investigated was determined by immunohis tochemical staining for CD3, a lymphatic surface antigen. Following th e isolation of about 100-200 tumor cells, PCR-directed molecular genet ic analysis was performed. A highly informative allelotyping approach for the detection of loss of heterozygosity (LOH), determining BstUI- and VNTR-polymorphisms, a 100-bp marker directly localized in intron I of the p53 gene, as well as screening for mutations by single-strand conformation polymorphism analysis (SSCP) in exons 5-8, were used. Out of 44 renal-cancer specimens, 33 (75%) were informative for PCR-direc ted RFLP-analysis. Allelic loss at the p53 gene locus was observed in 10 of 33 cases (33%). No correlation between p53 gene alteration and T -stage, histological grade or histological differentiation could be ob served. Alterations in the p53 gene, as detected by a molecular geneti c as well as an immunohistochemical approach, were correlated to overa ll survival. During univariate analysis histological grade, lymphnode status and the presence of distant metastases could be identified as p rognostic parameters for overall survival. During multivariate analysi s none of the factors investigated remained an independent prognostica tor far survival. Summarizing these results, it seems unlikely that p5 3 gene alterations will serve as an important new factor for the clini cal prognosis of patients with renal-cell cancer. (C) 1995 Wiley-Liss, Inc.