Expression and significance of EGR-1, p53, p16 and CyclinD1 in nasopharyngeal carcinoma

Objective To investigate the expressions and effects of EGR-1, p53, p16, Cyclin D1 in Nasopharyngeal Carcinoma (NPC). Methods Expressions of EGR-1, p53, p16, and Cyclin D1 protein in paraffin-embedded specimens of 29 chronic nasopharyngitis, 45 NPC and 24 lymph-node metastasis were studied by immunohistochemical method (SABC). Results The positive rates of EGR-1, p16, and Cyclin D1 protein expressions in chronic nasopharyngitis were 44.83 %(13/29), 89.66 %(26/29) and 24.14 %(7/29) respectively, but no p53 protein expression. In NPC, the positive expression rates of the four proteins were 22.22 %(10/45), 91.11 %(41/45), 53.33 %(24/45) and 66.67 %(30/45), with significant difference compared with chronic nasopharyngitis respectively; and in lymph nodes metastasis were 16.67 %(4/24), 79.17 %(19/24), 70.83 %(17/24) and 75.00 %(18/24) with significant difference compared with those of chronic nasopharyngitis and NPC respectively except for p16 protein. Spearman correlation analysis showed that there were no significant correlation between the expression of EGR-1 and p53, p16, Cyclin D1 respectively both in NPC and in lymph nodes metastasis. In NPC, the expression of p53 showed a positive correlation with the expression of p16; and in lymph nodes metastasis the expression of Cyclin D1 showed positive correlation with the expressions of p16 and p53. Conclusions The expression of EGR-1 protein was significantly decreased both in NPC and in lymph-node metastasis, which suggested that Egr-1 gene may be a tumor suppressor gene and have an important effect in the pathogenesis and the progression of NPC. The overexpression of p53 and Cyclin D1 also have an important role in NPC, but p16 probably have no biological significance in NPC.