BACKGROUND: We evaluated the characteristics of nasopharyngeal carcinoma in Korea, including its clinical, pathologic, and molecular features, especially emphasizing on the EBV strains involved, latent membrane protein 1 (LMP1) expression, and the alterations of matrix metalloproteinase 9 (MMP9) and E-cadherin expression. METHODS.: The presence of EBV was evaluated by EBER in situ hybridization, and the expression of LMP1, MMP9, and E-cadherin by immunohistochemistry. The characterization of EBV type and LMP1 variant was performed by PCR. RESULTS: EBER was detected in 55 of 57 cases (96%) of nonkeratinizing carcinoma (NKC) and undifferentiated carcinoma, but in only four of nine cases (44%) of squamous cell carcinoma (SCC). EBER positivity was much higher in the group with nodal metastases (p =.003). The predominant strain of EBV infection was type A (81%) and a 30-bp deletion LMP1 variant (77%). All EBER-positive SCCs were infected with EBV type A. LMP1 expression was detected in 36 of 59 (61%) patients with latent EBV infection and MMP9 in 41 of these 59 (69%). LMP1 positivity was much higher among the patients aged 50 years and younger. MMP9 expression was associated with LMP1 expression (p =.008), and nodal and distant metastasis (p =.019, p =.045). Loss of E-cadherin expression was correlated with MMP9 and nodal metastasis. The survival rate was much lower in patients with a higher TNM classification, stage, and a histology of SCC. EBER positivity was associated with a better prognosis in the Kaplan-Meier test, but had no prognostic value by Cox regression analysis. Loss of E-cadherin expression and nodal metastasis were also correlated with local recurrence and distant metastasis. CONCLUSION: EBV type and LMP1 variant had no significant influence on the clinicopathologic properties of tumor. However, there was a tendency toward a better survival in the EBV type B group. Histology and clinical staging were the two most important prognostic factors. Copyright 2004 Wiley Periodicals, Inc.
BACKGROUND: We evaluated the characteristics of nasopharyngeal carcinoma in Korea, including its clinical, pathologic, and molecular features, especially emphasizing on the EBV strains involved, latent membrane protein 1 (LMP1) expression, and the alterations of matrix metalloproteinase 9 (MMP9) and E-cadherin expression. METHODS.: The presence of EBV was evaluated by EBER in situ hybridization, and the expression of LMP1, MMP9, and E-cadherin by immunohistochemistry. The characterization of EBV type and LMP1 variant was performed by PCR. RESULTS: EBER was detected in 55 of 57 cases (96%) of nonkeratinizing carcinoma (NKC) and undifferentiated carcinoma, but in only four of nine cases (44%) of squamous cell carcinoma (SCC). EBER positivity was much higher in the group with nodal metastases (p =.003). The predominant strain of EBV infection was type A (81%) and a 30-bp deletion LMP1 variant (77%). All EBER-positive SCCs were infected with EBV type A. LMP1 expression was detected in 36 of 59 (61%) patients with latent EBV infection and MMP9 in 41 of these 59 (69%). LMP1 positivity was much higher among the patients aged 50 years and younger. MMP9 expression was associated with LMP1 expression (p =.008), and nodal and distant metastasis (p =.019, p =.045). Loss of E-cadherin expression was correlated with MMP9 and nodal metastasis. The survival rate was much lower in patients with a higher TNM classification, stage, and a histology of SCC. EBER positivity was associated with a better prognosis in the Kaplan-Meier test, but had no prognostic value by Cox regression analysis. Loss of E-cadherin expression and nodal metastasis were also correlated with local recurrence and distant metastasis. CONCLUSION: EBV type and LMP1 variant had no significant influence on the clinicopathologic properties of tumor. However, there was a tendency toward a better survival in the EBV type B group. Histology and clinical staging were the two most important prognostic factors. Copyright 2004 Wiley Periodicals, Inc.