Figure A4.

GJA1 mRNA level in breast cancer clinical samples is lower in HER2-positive breast tumors in four datasets. (a) GJA1 mRNA level in breast tumors stratified by HER2 status determined as described in Material and Methods. In the legend, “Breast” indicates adjacent normal breast tissue. p value: * <0.05; ** <0.01; *** <0.001. (b) Expression of GJA1 vs. ESR1 mRNA in each subtype and in normal breast tissue. (c) Bootstrapped correlations between ERBB2 and GJA1 mRNA level either in pooled breast cancer tumors or in individual intrinsic subtypes and in normal breast tissue. Data from Vanvliet, NKI, Curtis Discovery and Curtis validation datasets. (d) GJA1 mRNA vs. pY1248 phosphorylated form of HER2 protein level determined by RPPA in breast tumors from the TCGA dataset.