A number of KCNN4 SNPs reside within the first intron of the gene, some of which may be associated as well with ER-positive breast cancer risk [29], however, whether or not dysregulated KCNN4 expression is the cause of this risk association and which role the genetic control of the KCa3.1 channel plays for breast cancer development is not clear. This evidence concerns the gene KCNN4 and breast carcinoma.