title: Preferential expression of the multidrug-resistance-associated protein (MRP) in adenocarcinoma of the lung.
abstract: The expression of multidrug-resistance-associated protein (MRP) was assessed in various types of untreated lung cancer using an immunohistochemical technique. MRP was abundantly expressed in 28 of 59 adenocarcinoma specimens (47%) and its expression was associated with the degree of glandular differentiation of the tumor. MRP expression in well-differentiated adenocarcinomas (56%) was higher than in poorly differentiated adenocarcinomas (22%) (p < 0.01). lower--20% in squamous-cell carcinomas, 20% in large-cell carcinomas and 0% in small-cell carcinomas and carcinoids. RT-PCR showed that the MRP-positive adenocarcinomas and squamous-cell carcinomas expressed mrp mRNA significantly. Immunoelectron microscopically, MRP was localized in the plasma membrane and rough endoplasmic reticulum. It is thus important to take MRP into account when considering chemotherapy for lung cancers because levels of mdr I gene product, another multidrug-resistance gene family, are low in untreated lung cancers.
authors.affiliation: Department of Pathology, Saitama Medical Center, Saitama Medical School, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Sugawara
authors.forename: H
authors.initials: H
authors.lastname: Yamada
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Sumizawa
authors.forename: S
authors.initials: S
authors.lastname: Akiyama
authors.forename: A
authors.initials: A
authors.lastname: Masunaga
authors.forename: S
authors.initials: S
authors.lastname: Itoyama
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000032:analysis*; D000230:Adenocarcinoma / Q000737:chemistry*; D000595:Amino Acid Sequence; D001483:Base Sequence; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000737:chemistry*; D008297:Male; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D016133:Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D018528:ATP-Binding Cassette Transporters; D027425:ATP-Binding Cassette, Sub-Family C Proteins