Abstract
Pituitary tumours develop at a high frequency in p27-knockout mice and retinoblastoma gene-knockout mice, which suggests that cell cycle regulatory genes, such as cyclin-dependent kinase inhibitor genes, are involved in the tumorigenesis of pituitary adenoma. Analysis of p21 and p27 gene abnormalities in human pituitary adenoma was performed in 28 pituitary adenomas by polymerase chain reaction-single-strand conformational polymorphism. No point mutations were detected in these genes. As no abnormalities of the p21 and p27genes were observed, and if these genes are indeed inactivated, it is likely to be via transcriptional or translational defects.