Genetic alterations and reduced expression of tumor suppressor p33ING1b in human exocrine pancreatic carcinoma

AIM:To detect the expression of p33ING1bprotein and thechange of p33ING1bgene in pancreatic carcinoma and toevaluate the significance of p33ING1bin pancreatic cellcarcinogenesis.METHODS:Pathological specimens from pancreaticcarcinoma and matched non-tumor pancreatic tissues wereexamined for p33ING1bexpression and mutation byimmunohistochemistry,polymerase chain reaction single-strand conformation polymorphisms (PCR-SSCP) and lossof heterozygosity (LOH).RESULTS:The rate of p33ING1bprotein expression was 85%(34/40).A single germline missense mutation was detectedin I of 40 tumors located at codon 215:TGC-TCC (Cys-Ser).Fourteen (60.9%) of 23 tumor sampies showed LOH in ailof the informative markers tested,but no mutation wasdetected in these tumors and only two of the informativetumors lacked expressions of p33ING1bprotein.CONCLUSION:Mutation and loss of expression are notthe main reasons for the disfunction of p33ING1bin pancreaticcarcinoma,an abnormality at the level of chromosomeand/or transcription may inhibit their normal functions,potentially contributing to pancreatic cell carcinogenesis.