Paired BC cell lines obtained by CRISPR engineering and with an isogenic background having only the SNP variant genotype, as well as the LCLs lines were used to show (14) that knocking down of CALML3 abolished the SNP-dependent gene regulation of ZNF423 and BRCA1 expression in cells treated with E2 alone or with the addition of the SERMs. This evidence concerns the gene ZNF423 and breast cancer.