Colon carcinoma is known to have a familial tendency. 15% of patients with colorectal carcinoma have hereditary syndrome called: Hereditary Non-Polyposis Colorectal Caner (HNPCC). Patients that have colon carcinoma below the age of 50 years are likely to have this syndrome than older patients. The genetic alterations in this case includes mutations in Mismatch Repair Genes, the genes that are essential in correcting any �wrong� DNA synthesis during cell proliferation. The genetic hallmark of defective DNA Mismatch Repair is the presence of microsatellite instability (MSI-H). The most important of all these genes are MLH-1 and MSH-2 that compromise about 90% of all of these cases
Molecular studies for these patient are essential and are performed in most of large centers in the world for several reasons
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Patients with Microstalite instability (MSI-H) have better prognosis
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Serrated adenoma may be an important precursor to colorectal carcinoma in these patients
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Conventional adjuvant chemotherapy is less beneficial than patient with usual type of colorectal carcinoma, and patients with MSI-H tumors could in fact be worsened by chemotherapy
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Patients with this syndrome could have more than one carcinoma, example endometrial adenocarcinoma in females affected with this syndrome
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Family members for patients expressing MSI-H should be examined for this gene and screened for colorectal carcinoma by endoscopy at an annul basis
The histopathology of Patients with this syndrome have carcinomas usually in the right side of the colon with poor differentiation, unusual histologic types (mucinous, medullar and signet ring cell histology), absence of dirty necrosis, expansile growth pattern, numerous tumor infiltrating lymphocytes and prominent peritumoral lymphoid nodules
In our effort to bring the best of clinical tests to medical practice in Jordan, we would like to announce that these tests are available now in Jordan in our lab only
Please contact us for any further inquiries
Dr. Hussam Abu-Farsakh
American Board of Anatomic & Clinical Pathology, and Cytopathology