title: MDR1/P-glycoprotein expression in colorectal cancer.
abstract: Drug resistance to multiple chemotherapeutic agents is considered a major cause of chemotherapy failure. An extensively studied and relatively well understood type of cellular drug resistance is P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). Pgp acts as an energy-dependent drug efflux pump, thereby decreasing the intracellular drug concentration and causing drug resistance, in in vitro experiments. Colorectal cancer and colorectal mucosa generally express high levels of Pgp, and this may contribute to the general unresponsiveness of colorectal cancer to natural product, anticancer drugs. The controversies concerning the prognostic role of Pgp expression and its contribution to tumour aggressiveness, and possible reasons for the disappointing results of clinical MDR reversal trials in colorectal cancer are discussed.
authors.affiliation: Department of Medical Oncology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: S C
authors.initials: SC
authors.lastname: Linn
authors.forename: G
authors.initials: G
authors.lastname: Giaccone
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D002986:Clinical Trials as Topic; D015179:Colorectal Neoplasms / Q000378:metabolism*; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D015870:Gene Expression; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D009363:Neoplasm Proteins