DNA PLOIDY IN PANCREATIC NEUROENDOCRINE TUMORS

The nuclear DNA content of 17 pancreatic neuroendocrine tumors was measured from paraffin-embedded tissue with flow cytometry. The tumors were classified by immunostaining with antisera for synaptophysin, insulin, gastrin, glucagon, pancreatic polypeptide, somatostatin, and vasoactive intestinal polypeptide. Eight (47%) of the 17 tumors were aneuploid, and two (12%) were multiploid (had two aneuploid stemlines of cells). Seven of the eight insulinomas, one of the four gastrinomas, and two of the four nonspecified neuroendocrine tumors had an abnormal nuclear DNA content. The DNA indices of the aneuploid and multiploid cases ranged from 1.13 to 1.93, and three cases had a DNA index greater than 1.50. During the follow-up for up to 16 years (mean, 7 years), one patient with diploid nonspecified tumor died of the disease, another patient with a multiploid gastrinoma had metastatic disease develop, and a third patient with a multiploid nonspecified tumor was alive with the disease. The authors conclude that many neuroendocrine tumors of the pancreas have an abnormal nuclear DNA content as measured by DNA flow cytometry. DNA multiploid pancreatic neuroendocrine tumors may be associated with a less favorable clinical course, but this needs to be confirmed in additional studies.