title: P53 gene mutations in pituitary carcinomas.
abstract: Although p53 overexpression detected by immunohistochemistry has been reported in pituitary adenomas and carcinomas, genetic mutations in the p53 gene have not been previously detected in these tumors. We analyzed a series of eight pituitary adenomas and six pituitary carcinomas by immunohistochemistry, polymerase chain reaction amplification, and sequencing of p53 exon 5 through exon 8 for genetic mutations. Three carcinomas showed more than 20% expression of p53 protein in the tumor cells. One of these tumors with 60% overexpression of p53 protein had a mutation in codon 248, a common "hot spot" for p53 mutation, while the other carcinoma with 90% overexpression of p53 protein had a mutation in codon 135. All adenomas were negative for p53 mutations and had 15% of the cells expressing the p53 protein. Analysis of control tumors including four lung carcinomas with proven p53 mutations also had greater than 85% of the tumor cells overexpressing p53 protein. Two breast carcinoma cell lines with known p53 mutations, MBA-MD 231 and MBA-MD-486, also showed greater than 85% of the tumor cells overexpressing p53. These results show that p53 mutations are present in a subset of pituitary carcinomas and are usually associated with a high percentage of tumor cells overexpressing the p53 protein.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tanizaki
authors.forename: Long
authors.initials: L
authors.lastname: Jin
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Scheithauer
authors.forename: Kalman
authors.initials: K
authors.lastname: Kovacs
authors.forename: Federico
authors.initials: F
authors.lastname: Roncaroli
authors.forename: Ricard V
authors.initials: RV
authors.lastname: Lloyd
mesh_terms: D000236:Adenoma / Q000235:genetics; D000328:Adult; D000368:Aged; D001483:Base Sequence; D002277:Carcinoma / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D016158:Genes, p53 / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010911:Pituitary Neoplasms / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis
chemical_list: D016159:Tumor Suppressor Protein p53