Expression of the developmental and oncogenic PAX2 gene in human prostate cancer

Purpose: In the human prostate cancer cell lines LNCaP, DU145 and PC3, 27 p rimary prostate cancers, 10 benign prostatic hyperplasia specimens and 5 no rmal prostates we investigated the expression pattern of PAX2, a member of the PAX family of developmental control genes. PAX2 is expressed at high le vels in developing undifferentiated cells of the urogenital system and is r epressed upon terminal differentiation with no expression in normal adult c ells. It is also been shown to be a proto-oncogene in mice and is expressed in human renal cell carcinoma. Materials and Methods: PAX2 expression was assessed at the RNA level by rev erse transcriptase-polymerase chain reaction and Southern blot analysis usi ng specific sets of nucleotides. The expression pattern of PAX2 was reconfi rmed at the protein level by immunofluorescence in the cell lines, and by W estern blot analysis in primary human prostate cancers and benign prostatic tissue. Results: Using reverse transcription-polymerase chain reaction combined wit h Southern hybridization PAX2 expression was detected in 52% of primary can cers and all 3 cell lines. PAX2 expression in these samples was confirmed a t a protein level using immunoblotting and immunofluorescence. PAX2 messeng er RNA was not detected in any benign or normal prostatic samples. Immunobl otting of protein from benign prostatic hyperplasia samples confirmed the l ack of expression of PAX2 protein. Conclusions: The expression of PAX2 in prostate cancer compared to nonmalig nant prostates is statistically significant (Fisher's exact test p = 0.0004 ). These results suggest a possible role for PAX2 in prostate cancer. Altho ugh previous studies have suggested a role for PAX2 for supporting prolifer ation in undifferentiated cells, no correlation of PAX2 expression with Gle ason score was found in prostate cancer.