Cytogenetics of multiple endocrine neoplasia syndrome. II. Chromosome abnormalities in an insulinoma and a glucagonoma from two subjects with MEN1.

Cytogenetic analysis of two pancreatic islet tumors, an insulinoma and a glucagonoma was ascertained in two subjects with multiple endocrine neoplasia type 1 (MEN1). The insulinoma had a modal peak at 84 chromosomes. Most cells were pseudotetraploid, and in all cells the normal chromosomes were represented in varied numbers, i.e., from 1 to 7 copies. The tumor had 5 characteristic and consistent marker chromosomes which were identified as deletions of chromosomes 1, 2, 7, 16, and 17. All metaphases had several double minute chromosomes (dmin) of variable size and possible intermediate structures between dmin and homogeneously staining chromosomal regions. The glucagonoma had a nearly equal proportion of normal metaphases and metaphases with structural and numerical abnormalities with no consistent trend.