Expression of CDK6 and FOXM1 in peripheral T-cell lymphoma and their significance

Abstract

Objective: To investigate the expression of CDK6 and FOXM1 in peripheral T-cell lymphoma (PTCL), and its correlation with clinicopathologic features and patient prognosis. Methods: The Oncomine was used for data mining and analyzing the expression levels of CDK6 and FOXM1 in PTCL. Immunohistochemistry (IHC) of EnVision method was used to detect the expression of CDK6 and FOXM1 proteins in 166 cases of PTCL diagnosed at Shanxi Provincial Cancer Hospital from January 2016 to December 2018, and 30 cases of lymph node with reactive hyperplasia as control. Results: Among the PTCL patients, 104 were male and 62 were female, aged from 3 to 85 years, with an average age of 53 years. Analyses of the Oncomine 4.5 database showed that mRNA expression of CDK6 and FOXM1 in PTCL tissues was significantly higher than that in normal tissue (P<0.05). IHC staining showed the positive rates of CDK6 and FOXM1 proteins in PTCL tissues were 27.7% (46/166) and 80.7% (134/166), respectively. The expression was mainly present in the nuclei of tumor cells, showing a diffuse, strongly positive pattern. The positive rates of CDK6 and FOXM1 proteins among the 30 cases of lymph-node reactive hyperplasia were 0 (0/30) and 30% (9/30), respectively. The expression of FOXM1 was mainly found in the lymphoid follicle germinal center, and not present in the T-zone cells. CDK6 protein, FOXM1 protein and the co-expression of CDK6 and FOXM1 proteins in PTCL were associated with higher Ann Arbor staging and international prognostication index score (P<0.05), and inversely associated with overall survival (P<0.05). Meanwhile, CDK6 protein expression was positively correlated with FOXM1 protein expression (P<0.05). Conclusions: CDK6 and FOXM1 may be new targets for the diagnosis and treatment of PTCL. The overexpression of CDK6 may lead to enhanced function of the transcription factor FOXM1, while the overexpression of CDK6 and FOXM1 also promotes the development and progression of PTCL.