Proteins of the bcl-2 family are important regulators of programmed cell death. Alterations in the expression of these proteins may contribute to the progression of cancer. Expression of bcl-2, bcl-x, bax and bak was investigated by immunohistochemistry and Western-blotting of regular and alterated renal parenchyma as well as in 57 renal cell carcinomas. Bcl-2, bcl-x and in part bax were found to be overexpressed in inflammed renal parenchyma, whereas atrophic tubuli predominantly stained for bcl-2 and to a lesser degree for bcl-x and bax. Only little bak expression was detected in alterated tubuli. Moderate to strong expression for bcl-2, bcl-x, bax and bak was found in 24, 38, 2 and 13 of 57 carcinomas, respectively. Bcl-2, bcl-x, bax and bak expression were correlated to tumor type. Chromophilic carcinomas stained stronger for bcl-2, bcl-x and bax, whereas chromophobic carcinomas stained stronger for bcl-x, bax and bak compared to clear cell carcinomas. Expression of bak correlated with that of bcl-x and with an unfavorable histology as indicated by nuclear grading in these tumors. Our findings suggest that expression of bcl-2 and bcl-x may be important for cell survival only in a subset of renal cell carcinomas, and that the anti-apoptotic effect of these proteins appears to be frequently bypassed possibly by other factors impeding programmed cell death.
Disease Annotations
