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Role of MSH2 in Colon Cancer. Meagan Parsons. *Hereditary Colon Cancer*. FAP - familial adenomatous polyposis germline mutations in the APC gene (“gatekeeper”) HNPCC - hereditary nonpolyposis colon cancer (a.k.a. Lynch syndrome )
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Role of MSH2 in Colon Cancer Meagan Parsons
*Hereditary Colon Cancer* • FAP - familial adenomatouspolyposis • germline mutations in the APC gene (“gatekeeper”) • HNPCC - hereditary nonpolyposis colon cancer (a.k.a. Lynch syndrome) • germline mutations in DNA mismatch repair genes (“caretaker”)
*HNPCC* clinical/diagnostic featuresHereditary Non-Polyposis Colon Cancer
*HNPCC* mode of inheritanceHereditary Non-Polyposis Colon Cancer • autosomal dominant • loss of heterozygosity
*MSH2* • mutS homolog 2, colon cancer, nonpolyposis type 1 (E. coli) • maps to human chromosome 2p22-21
*HNPCC* genetics • heterozygous for mismatch repair genes • hMSH2 and hMLH1 = tumor suppressors
*MSH2* mouse models • Black = +/+ • Green = G674A/+ • solid red = G674A/G674A • blue = -/- • Dotted red = backcross
*MSI* microsatellite instability • the HALMARK of Lynch Syndrome (HNPCC) • Defective MMR = MSI • 5 standard DNA markers: *BAT26*
*HNPCC* treatments • surgical management – partial colectomy • chemotherapy – need functional MMR • possible preventative treatment • aspirin • resistant starch (fiber)