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 tumor (PCT) of the pancreas is more favorable than the adenocarcinoma, a malignant form has been reported. There has been much controversy as to the histologic evidence for malignancy. The purpose of this study is to evaluate whether the ras oncogene mutation is present in the PCT, together with hormone receptor status and DNA flow cytometry that can be used to predict tumor aggressiveness.

MATERIALS AND METHODS

In 6 collected cases of PCT, estrogen receptors (ER) and progesterone receptors (PR) were detected by immunohistochemical techniques, DNA ploidy and S-phase fraction (SPF) were studied by flow cytometry, and H, K, and N-ras oncogene mutation were analyzed by polymerase chain reaction (PCR).

RESULTS

General strong positive immunostaining of PR and negative staining of ER are found in all 6 cases of PCT, including 5 adolescent girls and one 55-year-old women with areas of anaplastic transformation. Flow cytometry analysis revealed diploid DNA in all 6 cases but higher SPF in the anaplastic portion of the old one. None of the 6 cases showed H-, K-, or N-ras oncogene mutation.

CONCLUSIONS

These results suggest PR status and ras oncogene mutation appear to be not useful in predicting aggressive behavior. DNA ploidy and S-phase fraction may provide useful information for prognosis, but their more precise prognostic value of PCT needs a larger number of cases to clarify.