[Expression of PDGFRA and CMYC in extranodal NK/T-cell lymphoma and their prognostic implications]

Objective: To investigate the relationship between expression of PDGFRA/CMYC and clinicopathologic features of extranodal NK/T-cell lymphoma. Methods: Fifty-four cases of extranodal NK/T-cell lymphoma were included in the study.Immunohistochemistry was used to detect the expression of CD20, CD2, CD3, CD56, TIA1, GrB, Ki-67, PDGFRA and CMYC.In situ hybridization was performed to detect the presence of EBV encoded small RNA (EBER). Fifty cases of nasopharyngeal mucosal lymphoid tissue hyperplasia were used as normal control. Results: Among 54 cases of ENKTL, CD2, CD3, GrB, and TIA1 were expressed in all the tumors. CD56 was expressed in 47 cases (81.0%) and CD20 was not detectable in any cases. Ki-67 proliferative index expression of > 60% was found in 45 cases (83.3%). In situ hybridization for EBER was positive in all cases (100%). The positive expression rates of PDGFRA and CMYC in extranodal NK/T-cell lymphomas were 51.9%(28/54) and 53.7%(29/54), respectively, much higher than those in nasopharyngeal mucosal lymphoid tissue hyperplasia (0, P<0.05). There was a positive correlation between PDGFRA and CMYC (r=0.295, P<0.05). The expression of CMYC was correlated with clinical efficacy (P<0.05), but not with gender, age, Ann Arbor stage, B symptoms and therapeutic regimen (all P>0.05). The expression of PDGFRA was correlated with B symptoms (P<0.05), while not with gender, age, Ann Arbor stage, therapeutic regimen and clinical efficacy (all P>0.05). The co-expression of PDGFRA and CMYC was not correlated with gender, age, Ann Arbor stage, B symptoms, therapeutic regimen and clinical efficacy (P>0.05). Univariate analysis showed that the stage, clinical efficacy, CMYC protein and the co-expression of PDGFRA and CMYC were significantly correlated with the prognosis. The overall survival of the patients with CMYC positive expression was shorter than of that of the patients with negative expression (P<0.05). Multivariable Cox regression analysis further confirmed that clinical stage, CMYC protein expression, and the co-expression of PDGFRA and CMYC were independent prognostic factors in patients with extranodal NK/T-cell lymphoma. Conclusion: CMYC protein, and the co-expression of PDGFRA and CMYC can be as an independent prognostic factor in patients with extranodal NK/T-cell lymphoma and influence the prognosis of patients.