Colorectal Cancer

Hereditary Non-polyposis Colorectal Cancer

Hereditary Non-polyposis Colorectal Cancer

Introduction

The Hereditary Non-Polyposis Colorectal Cancer (Lynch Syndrome) is increased susceptibility of developing cancer of the colon and cancer of the endometrium, ovary, stomach, small intestine, liver, the 'upper urinary tract, brain and skin. The colon is free of polyps. Individuals with this syndrome have an 80% risk of developing cancer of the colon which two thirds occur in the right colon with an average age of diagnosis of 44 years. Here we have a case of a 25-year old man, who has a family history of cancer. His father and a paternal great-uncle (his grandfather's brother) died of colorectal cancer at ages 45 and 58 respectively. His father's sister developed endometrial cancer at age 53. When the coding sequence of his MLH1 gene was sequenced, he was found to be heterozygous for a mutation, K618A, in exon 16(Ponz De Leon, M., 2002).

Discussion

The Hereditary Non-Polyposis Colorectal Cancer (HNPCC) also known as Lynch Syndrome is a syndrome that is autosomal dominant congenital with a high-average degree of penetrance (30-70%). The disorder related to autosomal dominant is that links the development of cancer a genetic tendency to colorectal and family. There are two types:

Lynch syndrome I: characterized by the onset of colon cancer.

Lynch syndrome II: Including colorectal cancer, it involves in the development of tumors in the bile ducts, urinary tract and stomach(American Institute For Cancer Research, 1999).

Bioinformatics

The bioinformatics as one of its simplest definition is the claim of technology computers to the organization and examination of data biological. The terms including bioinformatics, systematic biology , and sometimes, Bio-computing , used in many situations such as synonyms, refer to interdisciplinary fields of study closely linked, requiring the use or development of techniques that include computer science , Applied Mathematics, Statics Mathematics, artificial intelligence, chemistry and biochemistry for troubleshooting, analyze data, or simulate systems or mechanisms, all of such biological, and usually (but not exclusively) at the molecular level. In this case we will analyze the key factors and the application of technology to tackle this issue(Tsigelny, I. F.,2002).

Incidence & prevalence 

Standardized annual incidence colon: from 25.9 to 45.8 / 100,000 men and from 17.4 to 28.4 / 100,000 women.

Subjects at risk for colorectal cancer:

Average risk patients: individuals over 50 years.

those at high risk (risk 2-5 times higher than for average-risk population): personal history of colorectal cancer, history of adenoma (polyp) greater than 1 cm, 1° to family history of colorectal cancer and degree of adenoma greater than 1 cm, a history of ulcerative colitis and Crohn's disease extent. (Risk of colorectal cancer by 10 to 25% over the life).

Subject to very high risk in hereditary forms (3% of colorectal cancers) and familial adenomatous polyposis colon cancer syndrome without polyposis (Lynch syndrome). Nearly one out of two will be diagnosed with colorectal cancer in these families(Almeida, M. D. R., 2001).

Causes

The cause of HNPCC in this case is genetic. They are due to mutations in MMR genes (Mismatch repair).Or we can say, here the genes are involved in repairing errors in DNA replication. These genes are:

The mutation is autosomal dominant and significantly increases the predisposition to colon cancer. If the mutation is present in a man, he has a risk of 70% to 80% of developing colorectal cancer before age ...