title: High frequency of  microsatellite instability in sporadic colorectal cancer patients in Iran.
abstract: Microsatellite  instability in sporadic colorectal cancer patients was assessed, and the  clinicopathological associations were evaluated in northeastern Iran, which is  a high-risk region for gastrointestinal malignancies. Microsatellite instability  (MSI) status of tumoral tissue, compared to normal tissue, was assessed with a  standard panel of MSI markers on paraffin-embedded surgically resected tissues  from 67 consecutive sporadic colorectal cancer patients. Eleven of the  patients were under 40 years old. Female patients were significantly younger  than male patients (mean age 54.2 vs 62.1 years, P = 0.020). MSI  analysis revealed 18 cases of MSI-H (26.9%), 11 MSI-L (16.4%) and 38 MSS  (microsatellite stable tumors; 56.7%). While a greater proportion of patients  consisted of males, 56.7 vs 43.3% females, MSI-H was more frequent in  females (34.5 vs 21.5%). MSI was associated with proximal location of tumor  (P = 0.003) and lower stages of tumor (P = 0.002), while MSS tumors were  associated with node metastasis. MSI has a higher frequency in sporadic colorectal  cancer patients, suggesting that molecular epidemiology of the genetic alterations  involved in colorectal cancer carcinogenesis has a different pattern in the  Iranian population, which deserves further epidemiological attention. The high  frequency of MSI-H in this population suggests that we should look at  microsatellite instability prior to chemotherapy to determine the most  appropriate chemotherapeutic strategy in our population.
authors.affiliation: Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Moghbeli
authors.forename: O
authors.initials: O
authors.lastname: Moaven
authors.forename: E
authors.initials: E
authors.lastname: Dadkhah
authors.forename: M
authors.initials: M
authors.lastname: Farzadnia
authors.forename: N M
authors.initials: NM
authors.lastname: Roshan
authors.forename: H
authors.initials: H
authors.lastname: Asadzadeh-Aghdaee
authors.forename: M M
authors.initials: MM
authors.lastname: Bahar
authors.forename: R
authors.initials: R
authors.lastname: Raeisossadati
authors.forename: M M
authors.initials: MM
authors.lastname: Forghanifard
authors.forename: S R E A
authors.initials: SR
authors.lastname: Bakhtiari
authors.forename: A
authors.initials: A
authors.lastname: Baradaran
authors.forename: M R
authors.initials: MR
authors.lastname: Abbaszadegan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D005819:Genetic Markers; D006801:Humans; D007492:Iran; D019656:Loss of Heterozygosity / Q000235:genetics; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged
chemical_list: D005819:Genetic Markers