Identification of Fibroblast Growth Factor-5 as an Overexpressed Antigen in Multiple Human Adenocarcinomas

Methodology for identifying tumor-associated antigens recognized by T cells has been successfully used to clone antigens from melanoma cells. Similar efforts for nonmelanoma tumors have had limited success with few antigens identified. To identify potentially relevant tumor-associated antigens expressed in renal cell carcinoma cell lines, a tumor-specific CTL clone was established from tumor-infiltrating lymphocytes from a regressing pulmonary lesion. This CTL recognized nonmutated fibroblast growth factor-5 (FGF-5). Quantitative real-time reverse transcription PCR revealed that FGF-5 was overexpressed in the majority of renal cell carcinomas, as well as in some prostate carcinoma and breast carcinoma lines. FGF-5 expression by quantitative real-time reverse transcription PCR in normal tissues was below the recognition threshold for this CTL. As a normal protein with significant overexpression by multiple adenocarcinomas and little normal tissue expression, FGF-5 represents an immunotherapy target with potential utility against a broad array of nonmelanoma cancers.