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Background & Objective: Iran is located in the esophageal cancer geographical belt. As multiple genetic alterations are responsible for the molecular pathogenesis of esophageal squamous cell cancer (ESCC), the role and frequency of HER2 expression, MMR deficiency, and PI3KCA mutation are not well defined. Methods: We carried out HER2/neu expression, dMMR/MSI high, and PI3KCA mutation analysis in specimens of patients with ESCC. We accessed archival tissue blocks related to specimens of 68 ESCC cases at the time of surgery following neoadjuvant chemoradiation. These patients underwent surgery during 2013-2018 at the Cancer Institute of Iran affiliated with the Tehran University of Medical Sciences in Tehran. Results: None of the patients showed HER2 expression, dMMR/MSI high, or PI3K mutations. Conclusion: dMMR/MSI-H and PI3KCA mutation and HER2 expression may not be reliable andfrequent targets for systemic therapy in patients with esophageal SCC. [ABSTRACT FROM AUTHOR]

Objective The most important tumor characteristic of Lynch syndrome (LS) is microsatellite instability (MSI). In the current study, BAT34c4 and BAT26 mononucleotide markers were evaluated as part of efforts to test a cost-effective panel for MSI testing in Iranian patients, comparing it with the Promega kit. Methods Amsterdam II clinical criteria were used to identify patients at risk for LS. The MSI status of these patients was determined using BAT34c4 and BAT26 markers, as well as the Promega kit. The results of both methods were compared, and the sensitivity and specificity of new short tandem repeat (STR) markers were estimated using statistical formulas. Results Of the 37 patients we studied who were at risk for LS, 27% showed MSI-high results, via the Promega kit. The same results were achieved for BAT34c4 and BAT26 separately. Conclusions The novel 2-marker kit for MSI testing has similar accuracy as the Promega kit at a lower cost, due to fewer markers and a more economical labeling method. [ABSTRACT FROM AUTHOR]

Background & Objective: Microsatellite instability is common in familial colorectal cancers. It can be tested by the molecular and immunohistochemical methods. There are very few studies which address comparing the clinicopathological characteristics of microsatellite stable (MSS) and microsatellite unstable (MSI) colorectal cancers from Iran. In this study, we aimed to evaluate the clinicopathological and immunohistochemical findings of MSS and MSI colorectal cancers in our Center as the largest Center of gastrointestinal surgery and oncology in the South of Iran. We also compared the immunohistochemical method vs. molecular study using DNA sequencing. Methods: For 5 years (2015-2019), 34 patients who underwent operation in the affiliated Hospitals of Shiraz University of Medical Sciences were clinically suspected to microsatellite instability (MSI). The molecular diagnostic tests with DNA sequencing were performed. Clinicopathological and immunohistochemical findings of MSI colorectal cancers were compared with those who were stable. Results: In the South of Iran, MSI colorectal cancers were more common in males. These tumors were more common in the right side with more tendencies to produce mucin with lymphocytic infiltration. Conclusion: Immunohistochemistry would be a specific method for diagnosis of MSI colorectal cancers but may be associated with high rate of false negative results and of low sensitivity. Therefore, we recommend performing molecular studies by DNA sequencing in those colon cancers with clinical suspicion for MSI and negative immunohistochemical findings. [ABSTRACT FROM AUTHOR]

Purpose: Mismatch repair (MMR) is one of the DNA repair systems that correct mispaired bases during DNA replication errors. Polymorphisms in genes can increase susceptibility to the development of prostate cancer (PCa). In this study, we investigated mutL homolog 1 (MLH1) -93G>A (rs1800734) and mutS homolog 3 (MSH3) (rs26279) polymorphisms with the risk of PCa.Materials and Methods: In this study of Iranian population, 175 histopathologically confirmed (PCa) patients and 230 benign prostate hyperplasia (BPH) as the controls were recruited. The genotypes of MLH1 and MSH3 were determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method.Results: There was no significant difference of MLH1 (P = 0.4) and MSH3 (P?=?0.5) genotype distributions among PCa cases and controls. And also patients with PCa were not significant differences compared to those without in stage of cancer, grade of tumor, perineural invasion, and vascular invasion.Conclusion: Our results did not show adequate evidence for any significant association of MLH1 and MSH3 polymorphisms and PCa . [ABSTRACT FROM AUTHOR]

Background: Microsatellite instability, the main genetic element in HNPCC syndrome, is associated with a number of cancers, including ovarian epithelial carcinomas. These cancers have distinct characteristics compared to non-MSI related ones. Objectives: The present study aims at determining the prevalence of microsatellite instability in ovarian carcinomas and their associated factors in Iranian patients. Methods: Paraffin-embedded blocks, belonging to 37 patients with definite diagnosis of ovarian epithelial cancers, were retrieved from the archives. After DNA extraction from tumor tissue and PCR reaction, the results were assessed in accordance with melting curve analysis. Subsequently, the relationship among microsatellite status and tumor histology, grade, stage, and size were investigated statistically. Results: The predominant histological type was serous histology. Four out of 37 carcinomas were microsatellite unstable (10.8%) and only 1 was MSI-high type (2.1%). The MSI was more frequent among younger patients with unilateral, non-serous histology, nonhigh grade, and stage I tumors without omental involvement. After statistical analysis, the only significant relationship was found between histological type (non-serous) and microsatellite status. Conclusions: Microsatellite stable and unstable ovarian cancers may have different associations with various factors in a sample of Iranian women. The identification of these characteristics may help narrow down indications to test this prognostic and predictive genetic error. [ABSTRACT FROM AUTHOR]

Introduction: Colorectal cancer (CRC) is the third leading cause of cancer deaths in the world, and hereditary factors and family history are responsible for the incidence and development of the disease in 20 to 30% of cases. Lynch syndrome, or hereditary nonpolyposis colorectal cancer (HNPCC), is the most common hereditary form of CRC that is inherited in an autosomal dominant manner. This study consisted of a systematic literature review of research articles that described the prevalence of HNPCC in Iranian patients with CRC. Methods: A systematic literature search was conducted in the PubMed, Scopus, IranMedex, and Google Scholar databases to identify relevant articles that describe HNPCC or Lynch syndrome in patients with CRC in Iran. For this purpose, a keyword search of the following terms was employed: (((Hereditary nonpolyposis colorectal cancer OR HNPCC OR Lynch syndrome)) AND (colorectal cancer OR familial colorectal cancer OR colon cancer OR rectal cancer OR bowel cancer)) AND IRAN. All eligible documents were collected, and the desired data were qualitatively analyzed. Result: Of the 67 articles that were found via the initial database search, only 12 were deemed to be of relevance to the current study. These articles included a total population of 3237 and this sample was selected and qualitatively analyzed. The findings of the review revealed that the frequency of mutation in MLH1, MSH2, PMS2, and MSH6 genes varied between 23.1% and 62.5% among the studied families. This indicated that HNPCC is linked with up to 5.5% of the total cases of colorectal cancers in Iran. Conclusion: The results of this study revealed that the hereditary form of HNPCC or Lynch syndrome is significantly high among patients with CRC in Iran. [ABSTRACT FROM AUTHOR]

The aim of the present study was to determine the profile of mismatch repair (MMR) defects in Iranian colorectal cancer patients by using immunohistochemical staining for products of four MMR genes: MLH1, MSH2, PMS2, and MSH6. Tissue samples of 343 patients were immunostained for MLH1, MSH2, PMS2, and MSH6. Clinical and family history and survival data were compared between normal and abnormal staining patterns. Fourteen percent of the patients had abnormal nuclear staining for MMR proteins. MLH1 was absent in four, MLH1/ PMS2 in 15, PMS2 in five, MSH2 in 12, and MSH2/ MSH6 in 12 patients. These tumors were more proximal, had a nonsignificant better survival, and were more associated with positive family history. Estimation of this study of prevalence of hereditary nonpolyposis colorectal cancer in Iran was 5.5% of the total colorectal cancers. Along with the recommendations of the National Institute of Cancer, we recommend immunohistochemistry staining for MLH1, MSH2, PMS2, and MSH6 for determining the eligibility of patients for mutation analysis of MMR genes. [ABSTRACT FROM AUTHOR]

Objective: The most important tumor characteristic of Lynch syndrome (LS) is microsatellite instability (MSI). In the current study, BAT34c4 and BAT26 mononucleotide markers were evaluated as part of efforts to test a cost-effective panel for MSI testing in Iranian patients, comparing it with the Promega kit., Methods: Amsterdam II clinical criteria were used to identify patients at risk for LS. The MSI status of these patients was determined using BAT34c4 and BAT26 markers, as well as the Promega kit. The results of both methods were compared, and the sensitivity and specificity of new short tandem repeat (STR) markers were estimated using statistical formulas., Results: Of the 37 patients we studied who were at risk for LS, 27% showed MSI-high results, via the Promega kit. The same results were achieved for BAT34c4 and BAT26 separately., Conclusions: The novel 2-marker kit for MSI testing has similar accuracy as the Promega kit at a lower cost, due to fewer markers and a more economical labeling method., (© American Society for Clinical Pathology, 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Gastric cancer is the third leading cause of cancer-related death. Determining molecular and histopathologic tumor features, which may contribute to the development or progression of gastric cancer, can improve the prognosis. Expression patterns of DNA repair proteins such as MLH1, MSH2, MSH6, and PMS2 that are associated with microsatellite instability (MSI) are some of the markers that are useful in predicting the prognosis of gastric cancer., Purpose: The purpose was to determine the immunohistochemical expression pattern of MLH1, MSH2, MSH6, and PMS2 in tumor specimens of Iranian gastric carcinoma patients., Methods: In this prospective cohort, 186 consecutive patients with gastric cancer, attending Taleghani Hospital, were enrolled. The immunohistochemical expression patterns of MLH1, MSH2, MSH6, and PMS2 in tumor specimens among them were determined., Results: The results of this study demonstrated that 91.4% of our gastric cancer patients were negative for MSI, and 8.6% of them were MSI positive. The positive MSI was seen in 5.9% and 15.7% of male and female subjects, respectively, with a significant difference (P = 0.043). The other variables were not related to MSI results (P > 0.05)., Conclusion: According to the obtained results, the expression of MLH1, MSH2, MSH6, and PMS2 in tumor specimens is positive in 8.6% of the total Iranian gastric cancer sample size, which is mainly positive in female subjects. However, it is not related to the location and stage of the tumor., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Lynch syndrome (LS) increases the risk of many types of cancer, mainly colorectal cancer (CRC). The purpose of this study was to assess the prevalence of mismatch repair (MMR) deficiency in patients under the age of 50 with advanced adenomatous polyps, aiming at an early diagnosis of LS., Methods: This retrospective, cross-sectional study included eligible patients with advanced adenomas diagnosed ≤ 50 years of age registered between April 2014 and February 2017 at three pathology centers in Mashhad. Pathological records were reviewed, and colon tissue specimens were analyzed by immunohistochemistry (IHC) staining to identify proteins which serve as markers for LS as they are related to loss of MMR gene (MLH1, MSH2, MSH6, and PMS2) expression., Results: Of 862 consecutive patients, a total of 50 adenomas (54% males, 46% females of mean age 41.24 ± 6.5) met the eligibility criteria. Of the adenomas examined, 20 (40%) had a tubulovillous component, 34 (68%) had high-grade dysplasia, and 30 (60%) had were larger than 10 mm protrusions. None of the patients had loss of MMR protein expression., Conclusion: No individual with MMR genetic disorder was identified by IHC screening of early-onset advanced colorectal adenomas. This strategy is therefore not an effective strategy for detecting MMR mutation carriers.

Previous studies evidenced the critical role of the mismatch repair system in DNA damage recognition, cell cycle arrest, apoptosis and DNA repair. MLH1 and MSH2 genes belong to repairing complexes of mismatch repair system. The side effects of ionizing radiation on the human health were proved, but researches on the inhabitants of high background radiation areas, with extra-ordinary radiation exposure, showed that the prevalence of cancer or radiation-related diseases is not significantly higher than normal background areas. The city of Ramsar, in northern Iran, has the highest level of natural background radiation in the world and in this study, we aimed to evaluate the expression of MLH1 and MSH2 genes among the inhabitants of high background radiation areas of Ramsar compared to normal background radiation areas. In the present study, 60 blood sample from high and normal background inhabitants were collected and we MLH1, and MSH2 genes expressions in residents of high background radiation area compared with normal background radiation area were evaluated by Quantitative Real-Time PCR. Our results showed a significant upregulation of MLH1 in residents of high background radiation area. Also, there is a significant association between MLH1 and MSH2 gene expression in both sexes. Also, the increased expression of MLH1 in HBRA is notable. There is an increased expression of MLH1 in age above 50 and a decreased expression of MSH2 in ages under 50 years (P < 0.0001). These findings are suggesting the triggering of Mismatch Repair system in response to high-level of natural background radiation. • Ramsar in northern Iran has the highest level natural background radiation(HLNBR). • Prevalence of radiation-related diseases is not meaningful in Ramsar. • Significant upregulation of MLH1 was seen in residents of HLNBR area. • Results suggested the triggering of Mismatch Repair system in response to HLNBR. [ABSTRACT FROM AUTHOR]