PAPILLARY CYSTIC TUMORS OF THE PANCREAS - ASSESSMENT OF MALIGNANT POTENTIAL BY ANALYSIS OF PROGESTERONE-RECEPTOR, FLOW-CYTOMETRY, AND RAS ONCOGENE MUTATION

Background Although the biologic behavior of papillary cystic armor (P CT) of the pancreas is more favorable than the adenocarcinoma, a malig nant form has been reported. There has been much controversy as to the histologic evidence for malignancy. The purpose of this study is to e valuate whether the ras oncogene mutation is present in the PCT, toget her with hormone receptor status and DNA flow cytometry that can be us ed to predict armor aggressiveness. Materials and Methods. In 6 collec ted cases of PCT, estrogen receptors (ER) and progesterone receptors ( PR) were detected by immunohistochemical techniques, DNA ploidy and S- phase fr action (SPF) were studied by flow cytometry, and H, K and N-r as oncogene mutation were analyzed by polymerase chain reaction (PCR). Results. General strong positive immunostaining of PR and negative st aining of ER are found in all 6 cases of PCT, including 5 adolescent g irls and one 55-year-old women with areas of anaplastic transformation . Flow cytometry analysis revealed diploid DNA in all 6 cases but high er SPF in the anaplastic portion of the old one. None of the 6 cases s howed H-, K-, or N-ras oncogene mutation. Conclusions. These results s uggest PR status and ras oncogene mutation appear to be nor useful in predicting aggressive behavior: DNA ploidy and S-phase fraction may pr ovide useful information for prognosis, but their more precise prognos tic value of PCT needs a larger number of cases to clarify.