Prevalence of hereditary nonpolyposis colorectal cancer in patients with colorectal cancer in Iran: a systematic review

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.
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.
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.
The results of this study revealed that the hereditary form of HNPCC or Lynch syndrome is significantly high among patients with CRC in Iran.