[Expression and significance of P53 and P21 in nasal NK/T-cell lymphoma].

Objective: To investigate the significance of P53 and P21 expressions in nasal NK/T-cell lymphoma (NKTL) and their relationships with the clinical stage, prognosis, proliferation and apoptosis of tumor cells.

Methods: The clinicopathologic and follow-up data was collected from 62 patients with NKTL proven by pathological examination. Sixty-two cases of NKTL were examined for P53, P21 and Ki67 proteins with tissue microarray technique and immunohistochemistry. TUNEL method was used to detect apoptosis (apoptosis index, AD). The proliferation index (PI) was determined by the expression of Ki67 proteins.

Results: The positive rates of P53 and P21 protein expression in NKTL were 79.03% and 58.06% respectively. The positive rates of P53 in Ann Arbor stage I, II, III and lV NKTL were 69.57%, 75.00%, 86.67% and 100.00% respectively, while those of P21 were 47.83%, 56.25%, 60.00% and 87.50%. With the progression of tumor, the positive expression rates of P53 and P21 proteins gradually increased. And there were significant differences statistically between the expressions of P53/ P21 and Ann Arbor stage (P < 0.05). The expression of P53 was positively correlated with the expression of P21(r = 0.467, P < 0.05). The prognosis of P53 and P21 positive expression group was worse than that of negative expression group (P < 0.05). The expression of P53 protein was an independent prognostic factor. The intensities of P53 and P21 expressions were positively correlated with PI (r = 0.177, 0.184, P < 0.05), while not correlated with AI (P > 0.05).

Conclusion: The expressions of P53, P21 and Ki67 proteins are closely related with the pathogenesis and progression of NKTL. Combined detection of P53, P21 and Ki67 could be better to judge the biological behavior of NKTL.