ACTB and cancer: The mRNA expression levels of 16 cancer-associated genes (Ki67, STK15, Survivin, CCNB1, MYBL2, GRB7, HER2, MMP11, CTSL2, ER, PGR, BCL2, SCUBE2, GSTM1, CD68, BAG1) detected by both methods were normalized to 5 reference genes (ACTB, GAPDH, RPLPO, GUSB, TFRC).