Study of the frequency of DNA mismatch repair genes mutations in suspected hereditary non-polyposis colorectal cancer - HNPCC patients. A South American collaborative study

• Grant number: 05/05155-6
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2006
• End date: August 31, 2008
• Field of knowledge: Biological Sciences - Genetics - Human and Medical Genetics
• Principal Investigator: Benedito Mauro Rossi
• Grantee: Benedito Mauro Rossi
• Host Institution: Hospital A C Camargo. Fundação Antonio Prudente (FAP). São Paulo , SP, Brazil

Abstract

Study of the frequency of DNA mismatch repair genes mutations in suspected hereditary non-polyposis colorectal cancer - HNPCC - patients South American Collaborative Study Although few isolated studies about hereditary non-polyposis colorectal cancer (HNPCC) have been published, only in United States and Europe the efficacy of the molecular approach for the DNA mismatch repair gene mutations identification was tested. The objective of this study is to evaluate the microsatellite instability (MSI) test and immunohistochemistry (IMH) test for hMLH1/hMSH2 proteins in order to identify carriers for germline mutations in the hMLH1/hMSH2 mismatch repair (MMR) genes. The tumors frequencies according to the mutation identification will be studied also. One hundred unrelated HNPCC suspect patients with cancer (Amsterdam or Bethesda Criteria) will be selected from four different hereditary colorectal cancer registries: Hospital do Câncer (São Paulo, Brazil); Hospital Italiano (Buenos Aires, Argentina); Hospital da Universidade Católica (Santiago, Chile); Hospital de las Fuerzas Armadas (Montevideo, Uruguay). MSI and IMH tests will be performed in the tumor samples, as well as, sequencing in DNA lymphocytes in order to search germline mutations in the hMLH1/hMSH2 MMR genes. Correlation between dependent and independent variables will be made through qui-square test and logistic regression. Nowadays, all genetic counseling, including risk, tests, treatment and familial, is made based on American or European studies. This can not reflect the South-American population reality. This way, this is a very important study that can contribute in a singular and fundamental manner for the diagnosis, counseling and treatment of suspected HNPCC South-American patients and their families. (AU)