title: Up-regulation of the peripheral benzodiazepine receptor during human colorectal carcinogenesis and tumor spread.
abstract: The peripheral benzodiazepine receptor (PBR) is overexpressed in a variety of cancers. In Unio Internationale Contra Cancrum (UICC) III colorectal cancers, a high level of PBR overexpression correlates with poor prognosis. However, little is known about the role of PBR in the development and progression of colorectal cancer. This study addresses the up-regulation of PBR during colorectal carcinogenesis and tumor spread. One hundred sixteen consecutive patients undergoing surgery for colorectal cancer with either regional (59 patients) or distant metastases (57 patients) were followed-up for 5 years or until death. Twenty-four of the 59 patients with initial UICC stage III cancers later developed distant metastases. PBR overexpression in tumor specimens was determined by immunohistochemistry. UICC stage III patients with colorectal primaries highly overexpressing PBR developed metastases significantly more often than patients with low PBR overexpression in their primary carcinoma. In 54 of the 116 patients adenomas and/or metastases and/or recurrences were available to be studied for PBR up-regulation during colorectal carcinogenesis and tumor spread. PBR was found to be overexpressed in 86% of early and late adenomas. Furthermore, 85% of primaries and of 86% of metastases displayed PBR overexpression. PBR overexpression was also detected at the mRNA level as revealed by real-time PCR. The extent of PBR protein overexpression was equivalent in colorectal adenomas and carcinomas but slightly increased in metastases. These data suggest a functional role of PBR during colorectal carcinogenesis and tumor spread. Thus, PBR qualifies as a target for innovative diagnostic and therapeutic approaches.
authors.affiliation: Medical Clinic I, Institute of Pathology, and Department of Surgery, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Maaser
authors.forename: Patricia
authors.initials: P
authors.lastname: Grabowski
authors.forename: Yelda
authors.initials: Y
authors.lastname: Oezdem
authors.forename: Antje
authors.initials: A
authors.lastname: Krahn
authors.forename: Bernhard
authors.initials: B
authors.lastname: Heine
authors.forename: Harald
authors.initials: H
authors.lastname: Stein
authors.forename: Heinz
authors.initials: H
authors.lastname: Buhr
authors.forename: Martin
authors.initials: M
authors.lastname: Zeitz
authors.forename: Hans
authors.initials: H
authors.lastname: Scherübl
mesh_terms: D000236:Adenoma / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D018450:Disease Progression; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D018079:Receptors, GABA / Q000096:biosynthesis*; D015854:Up-Regulation
chemical_list: D018079:Receptors, GABA; C499229:TSPO protein, human