Microsatellite instability and mismatch-repair protein expression in hereditary and sporadic colorectal carcinogenesis.
نویسندگان
چکیده
Aberrant crypt foci (ACF) are microscopic clusters of altered colonic crypts considered premalignant lesions in the large bowel. Genomic instability at short tandem repeats in the DNA, referred to as microsatellite instability (MSI) is the hallmark of hereditary nonpolyposis colorectal carcinoma (HNPCC) caused by mutations in DNA mismatch-repair genes, mostly hMLH1 and hMSH2. In this study, we evaluated for MSI ACF (n = 16), adenomas (n = 18), carcinomas (n =22), and lymph node metastases (n = 3) from 17 patients with colorectal cancer positive for MSI. Ten patients were members of HNPCC families; 7 patients had no family history of cancer. MSI was found in 7 of 7 (100%) ACF and 11 of 12 (91%) adenomas from patients with HNPCC. MSI was not related to histology and size of ACF. A progressive increase in instability as estimated by the number of shifted bands was observed along the ACF-adenoma-carcinoma sequence. In contrast, two of nine (22%) ACF and none of six adenomas from patients with MSI sporadic carcinoma were unstable at microsatellite loci. hMLH1 or hMSH2 protein expression was altered only in MSI-positive premalignant lesions (ACF and/or adenomas), but not in all MSI-positive lesions in patients with HNPCC. These observations provide evidence of the premalignant nature of ACF in HNPCC and suggest that MSI is a very early event both in HNPCC and in sporadic colorectal carcinogenesis, although in the latter it seems infrequent.
منابع مشابه
سه موتاسیون ژرم لاین جدید در ژن MLH1 در بیماران مبتلا به سرطان کولورکتال ارثی
Abstract Background: Hereditary non-polyposis colorectal cancer is the most common cause of early onset of hereditary colorectal cancer. In the majority of Hereditary non-polyposis colorectal cancer families, microsatellite instability and germline mutation in one of the DNA mismatch repair genes in clouding MSH2, MLH1, MSH6 and PMS2 are found. The Objective of this study was to determine th...
متن کاملCharacterization of mutator pathway in younger-age-onset colorectal adenocarcinomas.
The high-frequency microsatellite instability (MSI-H) phenotype, frequently identified in hereditary nonpolyposis colorectal cancer (HNPCC), also accounts for approximately 15% of sporadic colorectal cancers. Microsatellite instability (MSI) occurs from the mutational inactivation of the DNA mismatch repair genes, i.e. hMSH2 and hMLH1 in HNPCC, as well as from epigenetic inactivation of hMLH1 i...
متن کاملMolecular Analysis of Microsatellite Instability in Hereditary Non Polyposis Colon Carcinoma Patients from North-East Iran
Background and Objectives: Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant cancer predisposition syndrome caused by germ-line mutations in DNA mismatch repair genes. Tumors arising as a result of these mutations display instability in a sequence area known as microsatellites. Studies have shown that some Bethesda markers (BAT25, BAT26) are more efficient than other...
متن کاملDiagnostic microsatellite instability: definition and correlation with mismatch repair protein expression.
Alterations of the length of simple repetitive genomic sequences (microsatellite instability, MSI) characterize a distinct mechanism of colorectal carcinogenesis. Such MSI has been found to be associated with hereditary nonpolyposis colorectal cancer (HNPCC) that involves mutation of the human mismatch repair genes hMSH2 and hMLH1 as well as many sporadic cancers of most tissue types. Although ...
متن کاملFrequent microsatellite instability in sporadic tumors of the upper urinary tract.
Urothelial carcinoma of the renal pelvis and ureter may develop sporadically or as a manifestation of hereditary nonpolyposis colorectal cancer. The majority of hereditary nonpolyposis colorectal cancer is caused by mutation of the human DNA mismatch repair (MMR) genes and is detected by associated microsatellite instability (MSI). Seventy-three unselected urothelial carcinomas of the ureter an...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Cancer research
دوره 61 3 شماره
صفحات -
تاریخ انتشار 2001