Expression Of E-cadherin/catenin Complex And LMP1 And Their Significance In Nasopharyngeal Carcinoma

Objective: To elucidate the expression patterns of E-cadherin/catenin complex and LMP1 and their relationships to clinicopathological features in nasopharyngeal carcinoma (NPC). Materials and Methods: Formalin-fixed paraffin-embedded tissues from fifty-two non-keratinizing NPC patients and fifteen cases with chronic nasopharyngitis (CN) as control were examined immunohistochemically for the E-cad ,β-cat,α-cat and LMP1 proteins.The relationships among the expression of E-cadherin,β-catenin and α-catetin , as well as the relationship between the expression of the complex and LMP1 or clinicopathological features were analyzed . Results: (1)Abnormal expression rates of E-cad ,β-cat and α-cat in NPC cases were 48.1%(25/52),32.7%(17/52) and 34.6%(18/52), respectively, with reduced expression of the proteins ,while CN control groups strongly expressed E-cad ,β-cat and α-cat staining at plasmic membrane in all normal epithelial cells.The difference between the expression of the complex in NPC and that in CN was statistically significant( P<0.01) . Five cases of NPC(9.62%,5/52)showed markedly abnormal nuclear or cytoplasmic staining in tumor cells while no such evidence was observed in E-cad or α-cat expression in all cases studied. Furthermore,we found that there were possitive correlations between the expression of E-cad and α-cat (P<0.01,r=0.594), β-cat and α-cat (P< 0.01,r=0.527),E-cad and β-cat (P<0.05,r=0.314),respectively. (2)30.8% of NPC cases (16/52) showed possitive expression of LMP1 with membranous or cytoplasmic staining in tumor cells ,but all epithelial cells in both CN control group and para-carcinoma tissues were negative for LMP1 ( P<0.01). Unexpectedly, no correlation was elicited between LMP1 and E-cadherin/catenin complex expression.(3)The serological VCA-IgA titers of NPC cases with normal α-cat expression pattern were significantly higher than that of NPC cases with abnormal α-cat expression ( ~X ±SD: 3.67 ±0.65 and 2.84 ±1.1 ,respectively , logarithmically transformed data,P=0.008) . There were no other evidence indicating the correlation between the E-cadherin/catenin complex or LMP1 expression and the clinicopathological features (age ,sex, histopathological type, TNM staging,lymph node,VCA-IgA titer). Conclusion: Our findings suggest that :(1)Reduced expression of E-cad/β-cat/α-cat complex is commonly seen in non-keratinizing carcinoma of nasopharynx.This condition might be an early event in the development of NPC.During the progression of NPC, the E-cad/β-cat/α-cat complex expression may be unstable. (2) There are possitive correlations between the expression of E-cad and α-cat, β-cat and α-cat,E-cad and β-cat,respectively. (3) High titers of serological VCA-IgA in NPC patients correlate with normal expression pattern of α-cat, suggesting that regaining ofα-cat expression may occur in the pathological process of NPC.(4) LMP1 plays an important role in the early invasion of NPC.It might not correlate with the expression of E-cad/β-cat/α-cat complex.But they both function in the development of NPC.