BRCA1 and breast cancer: One of the notable findings in this study is that Fgfr2 suppresses expression of BRCA1, which is a well‐known breast cancer suppressor gene in humans and mice.[25, 39, 40] About one‐third of all sporadic breast cancers have low BRCA1 levels even though they are WT for BRCA1.[41] Thus, BRCA1 may undergo transcriptional regulation.