title: RAD50/MRE11/NBS1 proteins in relation to tumour development and prognosis in patients with microsatellite stable colorectal cancer.
abstract: RAD50/MRE11/NBS1 complex is essential for DNA double-strand break repair and for maintaining genomic integrity. In this study, we immunohistochemically examined MRE11, NBS1 and RAD50 expression in primary CRCs (n=208), the corresponding distant (n=41) and adjacent normal mucosa (n=130), and lymph node metastases (n=26), and investigated their clinicopathological significance in colorectal cancers (CRCs). We found that the intensity and percentage of MRE11 and NBS1 in primary CRCs were positively correlated with each other and with RAD50 (P<0.0001). Strong expression of MRE11, NBS1 or combined RAD50/MRE11/NBS1 was related to MSS, positive hMLH1 expression, earlier tumour stage (TNM stage I and II) and favourable survival (P<0.05). A high percentage of MRE11 expression was associated with less local recurrence and high apoptotic activity (P<0.05). In MSS CRCs, the expression of MRE11 and NBS1 was stronger than that in normal mucosa (P<0.05), and strong expression of NBS1 in primary tumour was related to favourable survival of patients in TNM stage I and II (univariate analysis: P=0.03; multivariate analysis: P=0.07). In MSI CRCs, neither MRE11 nor NBS1 expression showed differences among normal mucosa, primary tumour and metastasis, or among clinicopathological variables. In conclusion, RAD50/MRE11/NBS1 proteins interacted with each other, which had different clinicopathological significance in MSS and MSI CRCs, and further, each component of the complex might have additional roles. NBS1 might be a prognostic factor for patients with MSS tumour in TNM stage I and II.
authors.affiliation: Department of Oncology, Institute of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: Jingfang
authors.initials: J
authors.lastname: Gao
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Gunnar
authors.initials: G
authors.lastname: Arbman
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Sun
mesh_terms: D017766:Acid Anhydride Hydrolases; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D045643:DNA Repair Enzymes / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis / Q000473:pathology; D000076228:MRE11 Homologue Protein; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D009687:Nuclear Proteins / Q000096:biosynthesis*; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C121766:MRE11 protein, human; C112156:NBN protein, human; D009687:Nuclear Proteins; D000076228:MRE11 Homologue Protein; D017766:Acid Anhydride Hydrolases; C112158:RAD50 protein, human; D045643:DNA Repair Enzymes