Adhesion molecules as prognostic factors in nasopharyngeal carcinoma

Objective/Hypothesis: To identify the significance of molecular markers in determining the risk of recurrence and distant metastases in nasopharyngeal carcinoma. Study Design: In this retrospective case study, we evaluated archival nasopharyngeal carcinoma specimens for patterns of expression of E-cadherin, β-catenin, c-erb-B2, and Ki-67, which have been demonstrated to be important in other tumors. Methods: Fifty-four cases of nasopharyngeal carcinoma were identified, with a maximum follow-up of 13 years. The histopathological sections were stained using an automated immunohistochemical stainer (NexES, Ventana Medical Systems, Tucson, AZ) for E-cadherin (Zymed Laboratories [San Francisco, CA] and Transduction Laboratories [Lexington, KY] clones), β-catenin (Zymed), c-erb-B2 (Ventana Medical Systems), and Ki-67 (Novocastra, Burlingame, CA). The numbers of positively staining cells were scored as follows: 0%, 1% to 33%, 34% to 66%, or greater than 67%. Results: E-cadherin (Zymed) stained positively in only one case. The Transduction Laboratories clone demonstrated a spectrum of staining in all cases, from complete to disrupted to no identifiable membranous staining. The staining was consistently absent at the advancing tumor border, regardless of stage. The loss of β-catenin expression did not correlate with that of E-cadherin or with clinical outcomes. No staining was identified for c-erb-B2. Ki-67 staining was variable and did not correlate with clinical outcomes. Conclusions: Altered expression or loss of E-cadherin, or both, may result in loss of function, particularly at the infiltrating edge, with resultant loss of cell polarity, cell migration, and eventual metastasis. The interpretation of E-cadherin staining depends on antibody source. In contrast to recent studies, β-catenin expression is not altered and c-erb-B2 expression not identified, suggesting that these markers are not important in the prognosis of nasopnaryngeal carcinoma.