Overexpression of mRNA encoding the GIRK1 subunit, the product of the KCNJ3 gene, may contribute significantly to the malignant properties of breast cancers: using expression profiling, Stringer et al. [8] observed that RNA derived from KCNJ3 was aberrantly and highly overrepresented in primary invasive breast carcinomas when compared to the corresponding healthy breast tissue. Here, KCNJ3 is linked to breast cancer.