Abstract 4635: FK506 binding protein 51 is a possible novel tumoral marker

Abstract

Abstract Very recently, we have identified FK506 binding protein 51 (FKBP51), an immunophilin phisiologically expressed in lymphocytes, as a protein associated with malignant melanoma. Its expression correlates with tumor aggressiveness and is maximal in metastatic lesions. We have also demonstrated that FKBP51 is a factor of resistance to genotoxic agents, including anthracyclins and ionizing radiations, because it promotes NF-kB activation. Aim of the present study was to investigate FKBP51 expression in solid tumors. Overall 60 samples, stored in our Patology section, of the following tumors: breast, colon, lung, pancreas, ovary and prostate (10 for each tumor), and a comparable number of normal tissue samples, were analysed for FKBP51 expression by immunohistochemistry. An intense signal was observed in all prostatic and ovarian adenocarcinomas analyzed, but only in a proportion of pancreatic cancer samples analyzed (mostly, esocrine pancreas tumors). Furthermore, an intense nuclear signal was observed in colon and lung adenocarcinomas. Immunohistochemistry was negative in breast cancer. Normal tissues of the same histotype showed very low or undetectable levels of FKBP51. We also measured FKBP51 mRNA levels in deparaffinized tissues from breast, pancreas, prostate and lung samples, both normal and tumoral, by Realtime PCR. All normal tissues analyzed, except for prostate, displayed mRNA levels lower than those of peripheral blood mononuclear cells (PBL). FKBP51 levels in prostate and PBL were similar. Increases in mRNA levels, from 3 to 30 folds, were found in prostate, esocrine pancreas and lung cancers, compared to normal tissue of the same histotype. Very low FKBP51 mRNA levels were found in breast cancer. In conclusion, our preliminary results show that FKBP51 expression increases in different solid tumors, including ovary, prostate, lung, colon, and esocrine pancreas, in comparison with the normal tissue counterpart. This study support the conclusion that deregulated FKBP51 can play a role in malignant transformation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4635.