Genetic heterogeneity and alterations in chromosome 9 loci in a localized region of a functional pituitary adenoma

The molecular alterations reported in pituitary adenomas include mutations at the G(s)alpha in somatotrophinomas, and hypermethylation of the p16 tumo r suppressor gene. There are, however, no re ports of genomic instability o r intratumor genetic heterogeneity in pituitary adenomas. We have studied t he microsatellite loci on the short arm of chromosome 9 (9p) and the DNA fi ngerprinting pattern, of adjacent compartments, about 2 mm across, in a fun ctional chromophobe pituitary adenoma secreting growth hormone and prolacti n. The microsatellite loci were studied by PCR amplification using locus sp ecific primers, while the DNA fingerprinting pattern was studied by randoml y amplified polymorphic DNA (RAPD) analysis. Normal leukocyte DNA was taken as control. Only one compartment (Ta) showed alterations in several of the microsatellite loci and in the RAPD pattern vis a vis corresponding normal DNA and also the other two compartments of the tumor. This provides eviden ce for the localized nature of genomic instability in this tumor. (C) 2001 Elsevier Science Inc. All rights reserved.