| Background:Extranodal natural killer (NK)/T-cell lymphoma (ENKTL) is a distinct subtype of non-Hodgkin’s lymphoma which is very rare in North America and Europe but rather common in Asia and South America. ENKTL has distinct morphology, immunophenotype, biologic features and clinical behaviors which are associated with an aggressive natural and poor survival rates. There has no clear guidance as its optimal therapy. It has been suggested that involved field radiotherapy may benefit for early stage patients, chemotherapy and hematopoietic stem cell transplantation may benefit for advanced stage patients. Chemotherapy regimens, such as CHOP, SMILE, and DeVIC, may add benefit for remission, but the overall prognosis of this disease is poor because of frequent relapse or resistance to treatment. Thus, sensitive biomarkers help guiding therapy and indicating were needed searching urgently.MYC is the most frequently amplified potent oncogene and the elevated expression of its gene product, the transcription factor c-Myc, regulating G1 phase of cell cycle, promoting DNA replication, and regulating cell growth, proliferation and differentiation.Ki-67 is a nuclear antigen expressed by dividing cells, has been considered to be a sensitive prognostic index indicating cell proliferation and clinical outcome in various tumors.Objective:The purpose of this study was to investigate c-Myc and Ki-67 expression in Extranodal natural killer/T-cell lymphoma, nasal type (ENKTL) and their correlation between clinicopathologic parameters and the prognostic importance of ENKTL.Methods:Immunohistochemistry for c-Myc and Ki-67 was performed on tissue sections from 53 patients diagnosed with ENKTL, and their correlation with clinicopathologic variables was assessed. We also made a comparison between c-Myc positive and negative ENKTL on proliferation index (PI); and analyzed relationship between expression of c-Myc and Ki-67 index. The survival was analyzed by Kaplan-Meier product-limit method.Results:Positive expression of c-Myc was shown in 64.2% of the patients, and high expression of Ki-67 was found in 66%. The PI in c-Myc-positive tumor cell was significantly higher than that in c-Myc-negative ones (P=0.005). The positive correlation between c-Myc expression and Ki-67 index was also found (r=0.454, P= 0.001). Patients of c-Myc expression was shown to be associated with unfavorable overall survival (OS) and decreased progression free survival (PFS) (P=0.000 and 0.013, respectively). High expression of Ki-67 was also shown to be correlated with worse OS and PFS (P=0.014 and 0.016, respectively). And patients expression of c-Myc+/Ki-67 high had the worst OS and PFS (P=0.002 and 0.027, respectively).Conclusion:c-Myc may play an important role in the carcinogenesis of NK/T cell lymphoma by promoting cell proliferation. Both c-Myc expression and Ki-67 high expression in ENKTL patients may be valuable indicators for predicting the survival of ENKTL patients. |
