Using immunohistochemistry for mismatch-repair (MMR) proteins (MLH1, MSH2, MSH6, and PMS2) and microsatellite instability analysis, we evaluated the status of 90 non-selected CRC Peruvian patients followed in a nationwide reference hospital for cancer (INEN, Lima).
Lynch syndrome, also known as hereditary non-polyposis colorectal cancer, characterized by predisposition to colorectal cancer and other associated cancers, is an autosomal-dominant disorder mainly caused by germline mutations in DNA mismatch repair (MMR) genes such as MLH1, MSH2, and MSH6.
Following the recommendations by the Evaluation of Genomic Applications in Practice and Prevention working group all colorectal cancers were immunohistochemically stained for the presence of MMR proteins MLH1, PMS2, MSH2 and MSH6, independent of clinical criteria.
Among 327 oncologists, MSI and/or IHC for MMR proteins were most frequently selected (n = 205; 64%), with 82% versus 53% choosing MSI/IHC testing in patients with strong versus no CRC family history, respectively (adjusted odds ratio [OR], 3.87; 95% CI, 2.07 to 7.22).
Carriers of MMR gene mutations who have already had a colorectal cancer are at increased risk of a greater range of cancers than the recognized spectrum of Lynch syndrome cancers, including breast and prostate cancers.
Moreover, we demonstrated that colibactin-producing <i>E. coli</i> induce inhibition of the mutL homologue 1 (MLH1) MMR proteins, which could lead to genomic instability.However, colibactin-producing <i>E. coli</i> were more frequently identified in microsatellite stable (MSS) CRC.
A systematic search by Southern blot analysis in a cohort of 439 hereditary nonpolyposis colorectal cancer (HNPCC) families for genomic rearrangements in the main mismatch repair (MMR) genes, namely, MSH2, MLH1, MSH6, and PMS2, identified 48 genomic rearrangements causative of this inherited predisposition to colorectal cancer in 68 unrelated kindreds.
Elevated Microsatellite Alterations at Selected Tetranucleotide repeats (EMAST) is a genetic signature found in up to 60% of colorectal cancers (CRCs) that is caused by somatic dysfunction of the DNA mismatch repair (MMR) protein hMSH3.
Hereditary nonpolyposis colorectal cancer (HNPCC) is the most frequent hereditary form of colorectal cancer and is caused by germline mutations in mismatch repair (MMR) genes.
The frequency of constitutional mutations within the MMR genes is 1% of all newly diagnosed CRC cases and the spectrum of mutations is potentially characteristic.
In summary, SATB2 expression is a relatively specific marker of lower GI tract origin; however, loss of SATB2 expression is more commonly seen in colorectal carcinoma with MMR protein deficiency and BRAF mutation.
Carriers of MMR gene mutations who have already had a colorectal cancer are at increased risk of a greater range of cancers than the recognized spectrum of Lynch syndrome cancers, including breast and prostate cancers.
Previous studies have shown that MMR gene mutation carriers are at increased risk of colorectal, endometrial, and several other cancers following an initial diagnosis of colorectal cancer.
MMR protein-deficient non-neoplastic colonic crypts were not identified in patients with sporadic MMR protein-deficient or MMR protein proficient colorectal carcinoma.
Bi-allelic germline mutations in MMR genes predispose to haematological malignancies, brain tumours, gastrointestinal tumours, polyposis and features of neurofibromatosis type 1 in early childhood.We report a brother and a sister with bi-allelic germline mutations in MSH2; a pathogenic deletion of the first 6 exons and a variant of the initiation codon (c.1A>G (p.Met1?)), whereas their phenotypes (four colorectal cancers, small bowel carcinoma and 15 adenomas at age 39 and 48, and colorectal cancer, endometrial cancer and four adenomas at age 33 and 44, respectively) are more suggestive of a mono-allelic pathogenic MMR gene mutation.
Lynch syndrome (LS) is an inherited disorder caused by a germline mutation in the DNA mismatch repair (MMR) genes and is associated with increased risk of various cancers, particularly colorectal cancer and endometrial cancer (EC).
High levels of MSI at mononucleotide and dinucleotide repeats in colorectal cancer (CRC) are attributed to inactivation of the MMR genes, hMLH1 and hMSH2.
Molecular and morphologic tumor characteristics, such as KRAS/BRAF mutation status, mismatch repair (MMR) protein expression, tumor growth pattern, and tumor cell budding, have been shown to be of key therapeutic and/or prognostic relevance in CRC.