Aims The aim of this study is to investigate the expression profiles of cell cycle related proteins in nasal extranodal NK/T cell lymphoma, nasal type (ENKTCL).

Methods The expression profiles of cell cycle related proteins were assessed with a cell cycle antibody array and validated by immunohistochemistry. Correlations between the expression levels of proteins and clinical outcomes of patients with nasal ENKTCL were evaluated.

Results The expression of full length ataxia telangiectasia mutated (ATM) in nasal ENKTCL significantly decreased compared with that in nasal benign lymphoid proliferative disease (NBLPD), but the expression levels of p-ATM, CHK2 and RAD51 significantly increased in nasal ENKTCL compared with that in NBLPD. Kaplan-Meier analysis showed that the expression levels of p-ATM and CHK2 in nasal ENKTCL were inversely related to overall survival (p=0.011 and p=0.025, respectively).

Conclusion Abnormalities in the ATM pathway may play a crucial role in the oncogenesis and chemoradiotherapy resistance of nasal ENKTCL.