Benedito Mauro Rossi

Mismatch repair genes in Lynch syndrome: a review

Lynch syndrome represents 1-7% of all cases of colorectal cancer and is an autosomal-dominant inherited cancer predisposition syndrome caused by germline mutations in deoxyribonucleic acid (DNA) mismatch repair genes. Since the discovery of the major human genes with DNA mismatch repair function, mutations in five of them have been correlated with susceptibility to Lynch syndrome: mutS homolog 2 (MSH2); mutL homolog 1 (MLH1); mutS homolog 6 (MSH6); postmeiotic segregation increased 2 (PMS2); and postmeiotic segregation increased 1 (PMS1). It has been proposed that one additional mismatch repair gene, mutL homolog 3 (MLH3), also plays a role in Lynch syndrome predisposition, but the clinical significance of mutations in this gene is less clear. According to the InSiGHT database (International Society for Gastrointestinal Hereditary Tumors), approximately 500 different LS-associated mismatch repair gene mutations are known, primarily involving MLH1 (50%) and MSH2 (40%), while others account for 10%. Much progress has been made in understanding the molecular basis of Lynch Syndrome. Molecular characterization will be the most accurate way of defining Lynch syndrome and will provide predictive information of greater accuracy regarding the risks of colon and extracolonic cancer and enable optimal cancer surveillance regimens.

ErbB family immunohistochemical expression in colorectal cancer patients with higher risk of recurrence after radical surgery

PurposeInvestigate ErbB family expression in colorectal cancer patients with higher risk of recurrence after surgical treatment.MethodsWe studied 109 individuals with high risk stage II and stage III patients submitted to radical surgery. ErbB expression was assessed by tissue microarray technique.ResultsThe immunohistochemical expression was considered positive for EGFR, ErbB2, ErbB3, ErbB4 membrane, and ErbB4 cytoplasmic in respectively 57.8%, 8.3%, 69.7%, 11%, and 19.3% of patients. ErbB3 negative expression was associated with lymphovascular invasion. EGFR, ErbB2, and cytoplasmic ErbB4 expression was not associated with prognosis. Membranous positive ErbB4 expression was an independent prognostic factor for recurrence. ErbB3 negative expression was an independent prognostic factor for recurrence and survival in the multivariate analysis.ConclusionsThe immunohistochemical expression of ErbB3 and ErbB4 may identify a subgroup with stage II and III colorectal cancer at higher risk of recurrence.

Frequency of extra-colonic tumors in hereditary nonpolyposis colorectal cancer (HNPCC) and familial colorectal cancer (FCC) Brazilian families: An analysis by a Brazilian Hereditary Colorectal Cancer Institutional Registry

The two main forms of hereditary colorectal cancer are familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC). Some families do not meet all the diagnostic criteria for HNPCC or FAP and are classified as familial colorectal cancer (FCC). Little information is available on the spectrum of tumors related to HNPCC and FCC in South America. Objective: To describe the frequency of malignant tumors in a group of Brazilian families with HNPCC or FCC in an Institutional Hereditary Colorectal Cancer Registry. Material and methods: The study included 61 families (29 HNPCC and 32 FCC) between January 1998 and June 2001. HNPCC families were clinically classified according to the Amsterdam Criteria I or II. FCC families were characterized by the presence of at least two individuals with CRC or extra-colonic tumors associated with the HNPCC spectrum, at least one of them being under 50 years of age. Results: In the 29 families with HNPCC, 201 patients with cancer were identified among 1241 individuals (589 men and 652 women). Among the 201 patients 223 tumors were observed: 137 CRC (55 in men and 82 in women) and 86 extra-colonic (37 in men and 49 in women). In the 32 families with FCC, 146 patients with cancer were identified among 1053 individuals (505 men and 548 women); 158 tumors were observed in 146 patients, 75 CRC (33 in men and 42 in women) and 83 extra-colonic tumors (47 in men and 36 in women). The most frequent extra-colonic primary sites among the HNPCC families were: endometrium (26.5%) and breast (26.5%) (women), and stomach (35.1%) (men). Among the FCC families, the most common primary sites were: breast (27.8%) (women), and stomach (44.4%) (men). Conclusion: The high frequency of endometrial and gastric cancer found was expected, since these tumors are part of the HNPCC spectrum, but the high frequency of breast cancer requires further molecular investigation to determine a possible hereditary predisposition associated with hereditary CRC.

Radiation and chemotherapy instead of surgery for low infiltrative rectal adenocarcinoma: A prospective trial

AbstractBackground: The objective of this prospective study was to determine the possibility of treatment based exclusively on chemotherapy and radiotherapy for patients with low infiltrative rectal tumors in an attempt to preserve sphincter function. Methods: Sixteen patients with rectal adenocarcinoma up to 3 cm above the pectineal line with initial indications for abdominoperineal resection (APR) were submitted to a 5040-cGy (28×180 cGy) radiotherapy dose and chemotherapy during the first 3 and last 3 days of radiotherapy, using 425 mg/m2/day of 5-fluorouracil (5FU) and 20 mg/m2/day of folinic acid. Levamisole was used at 150 mg/day for 3 consecutive days at 2-week intervals throughout the period of therapy. Patients with a complete response were not submitted to APR, but received additional brachytherapy for curative purposes with doses from 2000 to 3000 cGy. Patients with recurrence after a complete response, with partial response, or with no response were submitted to APR. Results: Six patients (37.5%) presented a complete response, five (31.25%) presented a partial response, and five (31.35%) did not respond. The disease-free interval ranged from 1 to 34 months (mean=11 months) among the six patients with complete response, and only one patient not submitted to APR is currently asymptomatic. Among the 15 patients with an indication for APR, three refused surgery because of full improvement of clinical symptoms and currently have tumor activity in the rectum. Mean patient follow-up was 23.8 months (8 to 43 months), and ten patients (62.5%) showed no evidence of active disease at last follow-up. Conclusions: The therapeutic schedule used was not effective in preserving sphincter function in patients with low infiltrative rectal adenocarcinoma, because responses, although very frequent, were only temporary.

Germ Line Mutations of Mismatch Repair Genes in Hereditary Nonpolyposis Colorectal Cancer Patients with Small Bowel Cancer: International Society for Gastrointestinal Hereditary Tumours Collaborative Study

Purpose: The aim of study was to determine the clinical characteristics and mutational profiles of the mismatch repair genes in hereditary nonpolyposis colorectal cancer (HNPCC) patients with small bowel cancer (SBC). Experimental Design: A questionnaire was mailed to 55 members of the International Society for Gastrointestinal Hereditary Tumours, requesting information regarding patients with HNPCC-associated SBC and germ line mismatch repair gene mutations. Results: The study population consisted of 85 HNPCC patients with identified mismatch repair gene mutations and SBCs. SBC was the first HNPCC-associated malignancy in 14 of 41 (34.1%) patients for whom a personal history of HNPCC-associated cancers was available. The study population harbored 69 different germ line mismatch repair gene mutations, including 31 mutations in MLH1, 34 in MSH2, 3 in MSH6, and 1 in PMS2. We compared the distribution of the mismatch repair mutations in our study population with that in a control group, including all pathogenic mismatch repair mutations of the International Society for Gastrointestinal Hereditary Tumours database (excluding those in our study population). In patients with MSH2 mutations, patients with HNPCC-associated SBCs had fewer mutations in the MutL homologue interaction domain (2.9% versus 19.9%, P = 0.019) but an increased frequency of mutations in codons 626 to 733, a domain that has not previously been associated with a known function, versus the control group (26.5% versus 2.8%, P < 0.001). Conclusions: In HNPCC patients, SBC can be the first and only cancer and may develop as soon as the early teens. The distribution of MSH2 mutations found in patients with HNPCC-associated SBCs significantly differed from that found in the control group (P < 0.001).

Frequency of extracolonic tumors in Brazilian families with Lynch syndrome: analysis of a hereditary colorectal cancer institutional registry

Lynch syndrome (LS) is caused by inherited germline mutations in mismatch repair (MMR) genes. It is one of the commonest forms of inherited predisposition to colorectal cancer (CRC), accounting for 2–5% of all CRC. LS is characterized by early age of onset, with a tendency for multiplicity and an increased risk for extra-colonic tumors at particular sites. In this study we have evaluated the frequency of extra-colonic tumors in 60 unrelated LS families fulfilling the Amsterdam criteria (ACI. ACII) from the Oncotree database of the Hereditary Colorectal Cancer Registry of the AC Camargo Hospital. All families’ pedigree was extensively analyzed, varying from 2 to 6 generations with a total of 2,095 individuals evaluated. As expected, colorectal cancer was the most frequent tumor in the families (334 cases). We found 200 extracolonic tumors among all individuals with a higher ratio in women (123 cases) than men (77 cases). By far, breast cancer (32 cases) was the most frequent extracolonic manifestation in women followed by endometrial (20 cases) and uterine cervix cancer (20 cases). For man, prostate (16 cases) and stomach (12 cases) cancer were the most frequent extracolonic tumors. It is well know that establishing the diagnosis is challenging and requires knowledge and surveillance. Thus, recognition of individuals and families with hereditary predisposition to cancer according to clinical and molecular features, combined with intensive surveillance and management programs, can contribute substantially to improve results related to the diagnosis and characterization of LS.

Characterization of germline mutations of MLH1 and MSH2 in unrelated south American suspected Lynch syndrome individuals

Lynch syndrome (LS) is an autosomal dominant syndrome that predisposes individuals to development of cancers early in life. These cancers are mainly the following: colorectal, endometrial, ovarian, small intestine, stomach and urinary tract cancers. LS is caused by germline mutations in DNA mismatch repair genes (MMR), mostly MLH1 and MSH2, which are responsible for more than 85% of known germline mutations. To search for germline mutations in MLH1 and MSH2 genes in 123 unrelated South American suspected LS patients (Bethesda or Amsterdam Criteria) DNA was obtained from peripheral blood, and PCR was performed followed by direct sequencing in both directions of all exons and intron–exon junctions regions of the MLH1 and MSH2 genes. MLH1 or MSH2 pathogenic mutations were found in 28.45% (34/123) of the individuals, where 25/57 (43.85%) fulfilled Amsterdam I, II and 9/66 (13.63%) the Bethesda criteria. The mutations found in both genes were as follows: nonsense (35.3%), frameshift (26.47%), splicing (23.52%), and missense (9%). Thirteen alterations (35.14%) were described for the first time. The data reported in this study add new information about MLH1 and MSH2 gene mutations and contribute to better characterize LS in Brazil, Uruguay and Argentina. The high rate of novel mutations demonstrates the importance of defining MLH1 and MSH2 mutations in distinct LS populations.

Prognostic factors in locally advanced colon cancer treated by extended resection

UNLABELLED The impact of clinical, pathologic, and surgical variables on the postoperative morbidity, mortality, and survival of patients undergoing extended resections of colon carcinoma were evaluated. METHODS The medical records of 95 patients who underwent extended resections for colon carcinoma between 1953 and 1996 were reviewed. In all cases, in addition to colectomy, 1 or more organs and/or structures were resected en bloc due to a macroscopically based suspicion of tumor invasion. The clinical, pathologic, and surgical parameters were analyzed. Overall survival rates were analyzed according to the method of Kaplan and Meier. Multivariate analysis was performed using the Cox proportional hazards model. RESULTS Eighty-six patients were treated by curative surgeries and the remaining by palliative resections. Invasion of the organs and/or adjacent structures and regional lymph nodes was found microscopically in 48 and 31 patients, respectively. The median follow-up without postoperative mortality was 47.7 months. The 5-year overall survival rates was 52.6%. The 5-year overall survival rates for patients undergoing curative and palliative surgeries was 58.3% and 0%, respectively. The mean survival time in the palliative surgery group was 3.1 months. Multivariate analysis showed that Karnofsky performance status was strongly related to the risk of postoperative complications (P = .01), and postoperative deaths were associated with the type of surgery and Karnofsky performance status at the time of admission (P = .001). CONCLUSIONS Some patients with locally advanced colon adenocarcinomas undergoing extended resections have a 5-year overall survival rates of 58.3%. Patients could benefit from palliative-intent procedures, but these measures should cautiously be indicated and avoided in patients with low Karnofsky performance status due to high rates of postoperative mortality and poor survival.

Mutational spectrum of the APC and MUTYH genes and genotype-phenotype correlations in Brazilian FAP, AFAP, and MAP patients.

BackgroundPatients with multiple colorectal adenomas are currently screened for germline mutations in two genes, APC and MUTYH. APC-mutated patients present classic or attenuated familial adenomatous polyposis (FAP/AFAP), while patients carrying biallelic MUTYH mutations exhibit MUTYH-associated polyposis (MAP). The spectrum of mutations as well as the genotype-phenotype correlations in polyposis syndromes present clinical impact and can be population specific, making important to obtain genetic and clinical data from different populations.MethodsDNA sequencing of the complete coding region of the APC and MUTYH genes was performed in 23 unrelated Brazilian polyposis patients. In addition, mutation-negative patients were screened for large genomic rearrangements by multiplex ligation-dependent probe amplification, array-comparative genomic hybridization, and duplex quantitative PCR. Biallelic MUTYH mutations were confirmed by allele-specific PCR. Clinical data of the index cases and their affected relatives were used to assess genotype–phenotype correlations.ResultsPathogenic mutations were identified in 20 of the 23 probands (87%): 14 in the APC gene and six in the MUTYH gene; six of them (30%) were described for the first time in this series. Genotype-phenotype correlations revealed divergent results compared with those described in other studies, particularly regarding the extent of polyposis and the occurrence of desmoid tumors in families with mutations before codon 1444 (6/8 families with desmoid).ConclusionsThis first comprehensive investigation of the APC and MUTYH mutation spectrum in Brazilian polyposis patients showed a high detection rate and identified novel pathogenic mutations. Notably, a significant number of APC-positive families were not consistent with the predicted genotype-phenotype correlations from other populations.

Ezrin expression as a prognostic marker in colorectal adenocarcinoma

Ezrin protein acts in the regulation of cytoskeletal and directly influences survival and tumor progression; there is an increase in its expression in metastatic cells and tissues in several types of cancer including colorectal cancer. 250 Patients with colorectal cancer submitted to surgery from 1995 to 2002. Protein expression was carried through by Tissue Micro Array immunohistochemical tests of paraffined neoplasic tissues and associated with clinical variables. Differentiation degree, lymph node invasion, metastasis at diagnosis, and palliative surgery were associated to a higher expression of the protein and survival. Higher expression of the Ezrin correlates with tumor aggressiveness and worse prognosis for colorectal cancer.