ANALYSIS OF THE GS ALPHA-GENE IN GROWTH HORMONE-SECRETING PITUITARY-ADENOMAS BY THE POLYMERASE CHAIN-REACTION DIRECT SEQUENCING METHOD USING PARAFFIN-EMBEDDED TISSUES

We investigated the prevalence of Gs alpha gene mutations in growth ho rmone (GH) secreting pituitary adenomas from Japanese patients with ac romegaly. Forty-five GH-secreting adenomas were examined for the prese nce of point mutations in codons 201 or 227 of the GS alpha gene using the polymerase chain reaction-direct sequencing method and deoxyribon ucleic acid extracted from paraffin-embedded tumor specimens. Mutation of codon 227 of the Gs alpha gene was not observed in any of the tumo rs, but a mis-sense mutation of codon 201 was identified in two tumors (4.4%). One lesion was a densely granulated GH cell adenoma in a pati ent with adenomatous goiter and breast cancer. The other was a mixed G H cell-prolactin cell adenoma in a patient with multiple endocrine neo plasia type 1 associated with parathyroid hyperplasia and a pancreatic islet cell tumor. The Gs alpha gene detected in parathyroid tissue an d pancreatic tumor tissue was of the wild type in this second patient, and the mutation was specific to the pituitary tumor. These results s uggest that point mutations of codons 201 or 227 of the Gs alpha gene may not be important mediators of oncogenesis for GH-secreting pituita ry adenomas in Japan.