COL4A2 and breast cancer: Via qRT‒PCR, we analysed and confirmed the expression of 9 genes involved in BC-related pathways, CTNNB, FGF2, GNB4, CDH2, FGFR1, CHRM3, ITGA9, SGK1 and COL4A2 (Supplementary material 1, Supplemental data, Figure S6, Panels A‒I), validating the results of the RNA‒Seq analysis.