Prostate cell lines vary in oncogenic ETS expression and RAS/ERK pathway activation. (A) The sensitivity and specificity of antibodies detecting oncogenic ETS proteins were tested by immunoblot of the indicated amount of purified full-length proteins. (B) Immunoblots show levels of four oncogenic ETS proteins, pAKT (PI3K/AKT activation), pERK (RAS/ERK activation), total ERK, and tubulin control in six prostate cancer cell lines (left) and three cell lines derived from normal prostate (right). (C) Immunoblots show levels of ETV4 and pERK in the indicated cell lines with or without U0126 (10 μM, 10 hr). The same cell extracts are loaded on one gel above the dashed line, and a second gel below. ETV4 is only visible in DU145 cells after a very long exposure, hence it is not observed in (A).