MAPK1 and neoplasm: Among the downregulated genes were DUSP6 (Dual Specificity Phosphatase 6), a key negative regulator of ERK [1], and ERRFI1 (ERBB Receptor Feedback Inhibitor 1, also called Mig-6), a tumor suppressor that curbs activation of EGFR and sustained signaling through the ERK pathway [32, 33].