Selective knockdown of HDAC1, HDAC2, and a combination of both HDAC1 plus HDAC2 has been reported to increase the expressions of P-gp, MRP-1, and MRP2 in cell lines derived from human colorectal adenocarcinomas (HCT-8 and HCT-116). The gene discussed is HDAC1; the disease is colorectal adenocarcinoma.