Expression analysis of endogenous retroviral elements belonging to the HERV-F family from human tissues and cancer cells.

Based on the primer binding site for Phe-tRNA, human endogenous retroviruses (HERVs) have been classified as HERV-F family members, HERV-F, HERV-FXA, HERV-Fb, and HERV-Fc. The HERV-F family was expressed in human placenta preferentially. We investigated pol fragments of HERV-F family in various human tissues and cancer cells. The pol gene was expressed in human placenta only among tissues (brain, prostate, testis, heart, kidney, liver, lung, placenta, skeletal muscle, spleen, thymus, uterus), but detected in various cancer cell lines (RT4, BT-474, HCT-116, TE-1, UO-31, Jurkat, A549, MCF7, OVCAR-3, MIA-PaCa-2, PC3, LOX-IMVI, AZ521, 2F7, U-937, and C-33A) except for PFSK-1 and HepG2 by RT-PCR analysis. Expression and sequencing data of the 37 clones imply that the pol gene of HERV-F family is active in cancer cells, which may have potential role related to cancer development.