G-C heterozygosis in mutS homolog2 as a risk factor to hereditary nonpolyposis colon cancer in the absence of a family medical history.

To detect the presence of point mutations in a small section of the mutS homolog2 (MSH2) gene in both healthy and affected persons treated at the General Hospital of the State of Sonora, a 353 base pair section of the MSH2 gene was amplified and sequenced from six persons affected by hereditary nonpolyposis colorectal cancer and from 19 healthy persons. The affected persons did not show the mutations reported in the scientific literature; however, six healthy persons were heterozygote and mutant-allele carriers. The heterozygote condition implies that carriers are candidates for the development of colorectal cancer. However, it is important to know the family medical history when investigating hereditary mutations.

Small Bowel Carcinoma in Young Patient Detected by Double-balloon Enteroscopy / 대한소화기학회지

A 17-year old female presented with a chief complaint of melena and epigastric pain. She had a family history of colon cancer, her mother having been diagnosed with hereditary nonpolyposis colorectal carcinoma (HNPCC). After close examination including double-balloon enteroscopy, the patient was diagnosed with small bowel carcinoma, in spite of her young age. Here we report this rare case of small bowel carcinoma in a young patient with a family history of HNPCC.

Hereditary Colon Cancer: Lynch Syndrome

Lynch syndrome is the most common familial colorectal cancer syndrome. It is linked to germline mutations in one of four DNA mismatch repair (MMR) genes. A comprehensive family history is one important way to identify at-risk individuals. The elucidation of the molecular genetics of this syndrome has made it possible to screen for the disorder with molecular tests. Microsatellite instability and/or immunohistochemistry followed by germline testing for mutations in MMR genes is now a standard approach for clinically suspected cases. Correctly recognizing Lynch syndrome is essential for the application of appropriate screening and surveillance measures. Close surveillance and risk-reducing operations can decrease cancer-related mortality. In addition, counseling is an important component of the management of any family with Lynch syndrome.

Hereditary Nonpolyposis Colorectal Cancer

Hereditary nonpolyposis colorectal cancer(HNPCC) is an autosomal dominantly inherited disease associated with a marked increase in cancer susceptibility, especially cancer of the colorectum. The frequency of HNPCC in the general population is yet to be determined, but HNPCC may account for as much as 2% to 5% of colorectal cancer, Colorectal cancer in HNPCC differs from sporadic colorectal cancer by an early age of cancer onset, proximal predominance of colorectal cancer, an excess of synchronous and metachronous colorectal cancer, and excess extra-colonic cancers. We have found 5 HNPCC families since 1992 when we reported first HNPCC family (KHU-Hl) In order to register the patients of HNPCC and to review the clinicopathologic feature and appropriate management, we have analysed 5 HNPCC families. Five HNPCC families included 16 colorectal cancer patients(14 males and 2 females). The average age of first diagnosis was 39. Among 16 patients, 8 patient were operated at the KyungHee University hospital and their operative and pathologic records were available. Two synchronous and seven metachronous cancers were founded, so that eight patients had 15 colorectal cancer lesions. Ten cancers were located proximal to splenic flexure and five were distal. Partial resection of colon was performed in seven cases except one when the first diagnosis was made and recurrence was founded in 5 patients. Recurrence was treated by total colectomy in 3 cases and subtotal colectomy in two. In conclusion, we re-confirmed that HNPCC patient should be treated by no less than a subtotal colectomy because of high multiplicity and high recurrence rate of partial resection.