Overexpression and genetic abnormality of p53 in parathyroid adenomas

To study the significance of p53 abnormality in parathyroid tumors, 32 para thyroid adenomas and 22 hyperplastic glands from 14 cases of secondary hype rparathyroidism were analysed using immunohistochemistry, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), single-strand conformation polymorphism (SSCP) and DNA sequencing. Immunohistochemical s tudy revealed p53 overexpression in four parathyroid adenomas, of which two showed diffuse and one showed focal nuclear pleomorphism. Genetic analysis disclosed allelic loss in one, and a point mutation (R290H) and a polymorp hism (L257 L) in another of the two other adenomas with diffuse nuclear ple omorphism. No abnormalities were discovered in the other two adenomas, alth ough one had a R72P polymorphism in exon 4, There was no evidence of malign ancy of the four tumors in either clinical or pathological terms. None of t he 22 hyperplastic glands showed p53 overexpression, These: results demonst rate that p53 abnormality can occur in benign parathyroid adenomas and is m ore prevalent in those with nuclear pleomorphism than in those without.