[The expression of p27^Kip1 and β-catenin in multiple endocrine neoplasia type 1-related parathyroid tumors]

Objective: To explore tissue expression of cyclin-dependent kinase inhibitor p27^Kip1 and β-catenin in multiple endocrine neoplasia type1 (MEN1)-related parathyroid tumors (MHPT). Methods: Immunohistochemistry was performed to analyze the expression of p27^Kip1 and β-catenin in parathyroid glands from 31 subjects with MHPT collected at Peking Union Medical College Hospital from 2002 to 2013. Five normal parathyroid glands were used as control. Results: In MHPT subjects, nuclear expression of p27^Kip1 was absent in 4 (12.9%), weak in 10 (32.3%) and moderated staining in 17 parathyroid specimens (54.8%), respectively. While, in normal subjects, the nuclear expression of p27^Kip1 was observed in all subjects and was stronger than that from MHPT subjects (P=0.001). As to the expression of β-catenin, normal parathyroid showed a distinct to moderate membrane staining, a moderate to weak cytoplasmic staining and negative nuclear staining. Similarly, MHPT exhibited a marked to moderate membrane (P=0.087), a moderated to weak cytoplasmic (P=0.357), and negative nuclear β-catenin staining. Conclusions: The expression of p27^Kip1 is reduced or absent in MHPT tissue, and no nuclear expression of β-catenin is observed in the tumors, which suggesting p27^Kip1, but not β-catenin nuclear accumulation, play a role in the development of the tumors.