Overexpression of cyclin E/Cdk2 and loss of p27 appears to be associated with a poor prognosis and might play a role in the treatment of GHPAs in the future.
We aimed to investigate the expressions of p27 kinase inhibitory protein 1 (p27<sup>Kip1</sup>) and calcium sensing receptor (CaSR) in adenomas and normal parathyroid tissue and to evaluate the relationship of these molecules with clinical and biochemical parameters in primary hyperparathyroidism (PHPT).
Immunohistochemical expression of phospho-Akt was found to be higher in the tumours than normal pituitaries, while the protein expression of nuclear p27 and PTEN was lower in the adenomas.
High Ki-67 proliferative index was seen in 2% of adenomas and 25% of carcinomas, whereas p27 expression was present in 80% of adenomas and 18% of carcinomas.
Positive p27 staining rates were significantly higher in serous adenomas (p=0.006) and in serous LMP tumors (p=0.013) than that in serous carcinomas (Fisher's exact test).