MAP2K1 and posterior cortical atrophy: Afatinib, an irreversible EGFR, HER2, and HER4 small molecule inhibitor, is currently being evaluated in clinical studies in combination with capecitabine (NCT02451553) or selumetinib (AZD6244), a MEK1/2 inhibitor (NCT02450656) for the treatment of advanced stage PCa or with gemcitabine/nab-paclitaxel for metastatic PCa (NCT02975141).