Pancreatic Cancer Research Today is a free monthly online journal that collates and summarizes the latest research about Pancreatic Cancer, including details on symptoms, causes, treatment, information.

Defective DNA mismatch repair in long-term (> or =3 years) survivors with pancreatic cancer.

Maple JT, Smyrk TC, Boardman LA, Johnson RA, Thibodeau SN, Chari ST

Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA.

BACKGROUND/AIMS: Defective DNA mismatch repair (MMR) in pancreatic cancer, reported in up to 13% of sporadic pancreatic cancers, may predict a good prognosis. To determine if long-term survival in pancreatic cancer could be attributed to defective DNA MMR, we ascertained its prevalence in 35 pancreatic cancer patients who survived > or =3 years after surgery. METHODS: We performed immunohistochemistry (IHC) for MMR proteins hMLH1, hMSH2, and hMSH6 in all 35 tumors and microsatellite instability (MSI) studies in 34/35 tumors using 10 microsatellite markers in paired normal and tumor DNA. Defective DNA MMR was defined as absence of protein expression on IHC and/or MSI in > or =30% of markers studied. RESULTS: On IHC, 3/35 (8.6%) tumors had defective DNA MMR. All 3 had absent expression of a DNA MMR protein (hMLH1 in 2 and hMSH2) and 2/3 also had MSI; the third could not be tested. Definitely 2, and probably all 3 patients had hereditary nonpolyposis colon cancer as determined by clinical and genetic profiles. CONCLUSION: Defective DNA MMR is uncommon in long-term survivors of pancreatic cancer and does not account for the survival benefit in those with sporadic pancreatic cancer.

Published 11 May 2005 in Pancreatology, 5(2): 220-7; discussion 227-8.
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