CCN4 and breast neoplasm: Other studies have also reported differences in HER2 expression in breast tumors according to the genotype of SNPs located at other genes with roles related to gene regulation (FOXP3, NOTCH3) (82, 83), hormone signaling (ESR1 and CYP19A1) (84–86) and proliferation/survival control (WISP-1, CASP8, KRAS, TGFBR2, VEGF-A and CCND3) (87–92).