ETV4 and posterior cortical atrophy: Upon confirming the expression of ERG, ETS-1, ETS-2 and ETV-4 (Fig. 1), we performed IP using an anti-ERG antibody to investigate whether ERG is associated with ETS-1, ETS-2 and ETV-4 in PC3 cell nuclear extracts, as well as in a pooled protein lysate sample prepared from the PCa tissue samples of five patients.