To assess the specific role of ERK1 or ERK2 activation in FGFR1 signaling-promoted FOXQ1 expression, we treated ERK1 knockout or ERK2 knockout DCIS-iFGFR1 cells generated previously 15 with vehicle or AP20187 and assayed FOXQ1 expression. The gene discussed is MAPK1; the disease is ductal breast carcinoma in situ.