AIM: To analyse the expression of multidrug resistance (MDR) related proteins at different steps in colorectal carcinogenesis. METHODS: The presence of three MDR related proteins (Pgp, MRP1, and LRP/MVP) was studied by means of immunohistochemistry in normal, adenomatous, and malignant colorectal epithelium. Formaldehyde fixed, paraffin embedded tissue sections of 17 samples of colorectal tissue were used (normal mucosa, n = 4; adjacent mucosa, n = 5; adenoma, n = 5; carcinoma, n = 3). RESULTS: For all three proteins, expression was found in the surface epithelium and the upper parts of the crypts in normal colon. In the adenomas, staining was seen along the complete length of the crypts. In the carcinomas analysed, all epithelium showed positive staining. Mucosa adjacent to either carcinoma or adenoma showed staining patterns mostly resembling those of normal mucosa, but sometimes some extension of staining was seen along the crypt. CONCLUSIONS: These proteins already show increased expression in the adenoma stage. In the absence of adequate mucin production in adenomas, MDR related proteins could be an important factor in protecting the epithelium against further environmentally induced genetic damage. This could be one of the reasons why only about 5% of colorectal adenomas will actually progress to carcinomas.
AIM: To analyse the expression of multidrug resistance (MDR) related proteins at different steps in colorectal carcinogenesis. METHODS: The presence of three MDR related proteins (Pgp, MRP1, and LRP/MVP) was studied by means of immunohistochemistry in normal, adenomatous, and malignant colorectal epithelium. Formaldehyde fixed, paraffin embedded tissue sections of 17 samples of colorectal tissue were used (normal mucosa, n = 4; adjacent mucosa, n = 5; adenoma, n = 5; carcinoma, n = 3). RESULTS: For all three proteins, expression was found in the surface epithelium and the upper parts of the crypts in normal colon. In the adenomas, staining was seen along the complete length of the crypts. In the carcinomas analysed, all epithelium showed positive staining. Mucosa adjacent to either carcinoma or adenoma showed staining patterns mostly resembling those of normal mucosa, but sometimes some extension of staining was seen along the crypt. CONCLUSIONS: These proteins already show increased expression in the adenoma stage. In the absence of adequate mucin production in adenomas, MDR related proteins could be an important factor in protecting the epithelium against further environmentally induced genetic damage. This could be one of the reasons why only about 5% of colorectal adenomas will actually progress to carcinomas.
Authors: P van der Valk; C K van Kalken; H Ketelaars; H J Broxterman; G Scheffer; C M Kuiper; T Tsuruo; J Lankelma; C J Meijer; H M Pinedo Journal: Ann Oncol Date: 1990 Impact factor: 32.976
Authors: M A Izquierdo; G L Scheffer; M J Flens; G Giaccone; H J Broxterman; C J Meijer; P van der Valk; R J Scheper Journal: Am J Pathol Date: 1996-03 Impact factor: 4.307
Authors: A B Schroeijers; G L Scheffer; M J Flens; G A Meijer; M A Izquierdo; P van der Valk; R J Scheper Journal: Am J Pathol Date: 1998-02 Impact factor: 4.307
Authors: M J Flens; G J Zaman; P van der Valk; M A Izquierdo; A B Schroeijers; G L Scheffer; P van der Groep; M de Haas; C J Meijer; R J Scheper Journal: Am J Pathol Date: 1996-04 Impact factor: 4.307
Authors: J Herbergs; A P de Bruïne; P T Marx; M I Vallinga; R W Stockbrügger; F C Ramaekers; J W Arends; A H Hopman Journal: Int J Cancer Date: 1994-06-15 Impact factor: 7.396
Authors: M J Flens; M A Izquierdo; G L Scheffer; J M Fritz; C J Meijer; R J Scheper; G J Zaman Journal: Cancer Res Date: 1994-09-01 Impact factor: 12.701
Authors: Samy A F Morad; James P Madigan; Jonathan C Levin; Noha Abdelmageed; Ramin Karimi; Daniel W Rosenberg; Mark Kester; Sriram S Shanmugavelandy; Myles C Cabot Journal: Biochem Pharmacol Date: 2013-01-24 Impact factor: 5.858
Authors: Tamás Micsik; András Lőrincz; Tamás Mersich; Zsolt Baranyai; István Besznyák; Kristóf Dede; Attila Zaránd; Ferenc Jakab; László Krecsák Szöllösi; György Kéri; Richard Schwab; István Peták Journal: Diagn Pathol Date: 2015-04-16 Impact factor: 2.644