Abstract
Intraductal papillaryโmucinous tumors (IPMT) consist of cells with varying histologic degrees of severity and exhibit multiple tumor loci; however, whether or not these lesions exhibit the same genetic changes has not been clarified. To investigate this point, we analyzed Kโras mutations in multiple IPMT lesions from each patient enrolled in our study and compared our findings to those for patients with ductal adenocarcinoma of the pancreas (DC). Twenty IPMT specimens and 7 DC specimens were resected, microdissected and analyzed for the presence of Kโras mutations. The mutated genes were then sequenced using a genetic analyzer. Kโras mutations were observed in 80% of IPMT and 100% of DC patients. More than 2 types of Kโras mutation were observed in the main tumors of 43.8% of IPMT and 0% of DC patients. Kโras mutations in peritumoral and separated lesions were observed in 66.7% and 62.5% of IPMT patients, respectively. At least one identical mutation between the main tumor and the peritumoral or separated lesions was recognized in all of the IPMT patients with those lesions. Different mutations from those in the main tumor were observed in 40% of IPMT patients with separated lesions. The survival curve of IPMTโcarcinoma patients with more than 2 types of Kโras mutation in the main tumor was better than that with one type of Kโras mutation. IPMT patients exhibit a remarkably genetic heterogeneity in main tumor and have good prognosis. ยฉ 2004 WileyโLiss, Inc.