The GAPDH gene did not belong to any list of top-500 stable probesets, while gene ACTB (as well as UBC) belonged to three lists of top-500 stable probesets, but was not present in top-500 list corresponding to a dataset of histologically normal epithelium from breast cancer patients and cancer-free prophylactic mastectomy patients (GSE20437). Here, GAPDH is linked to breast cancer.