R421 – Ubc9: A Novel Marker of Lymph Nodes Metastases in SCCHN

Abstract

Problem Lymph node metastases (LNM) are the single most significant prognostic factor in squamous cell cancer of the head and neck (SCCHN). Therapy often relies on the ability to detect disease in cervical lymph nodes. We previously demonstrated that Ubiquitin-conjugating enzyme (Ubc9), an enzyme involved in post-translational modification, is over-expressed in SCCHN compared to peritumoral adjacent mucosa. Furthermore, Ubc9 is not expressed in normal mucosa. The present study was designed to examine the expression of Ubc9 in SCCHN LNM and to determine whether Ubc9 may serve as a marker. Methods A portion of primary tumor, normal adjacent mucosa, when available, and metastatic lymph nodes were harvested from patients with a histologic diagnosis of SCCHN. Tissue specimens were immediately snap-frozen in liquid nitrogen. The frozen tissue specimens were stained with antibodies to Ubc9 using standard Immunohistochemical techniques. Results Twelve patients with SCCHN LNM were available for staining. Sites of primary tumor specimens included larynx (n=7) and oropharynx (n=3). All of the lymph nodes had strong expression of Ubc9 in the metastatic deposits of SCCHN but not in the surrounding lymph node tissue. Conclusion Detection of Ubc9 expression in cervical lymph nodes from patients with SCCHN may serve as a distinct molecular marker for the presence of lymph node metastases. The findings also suggest that Ubc9 plays an important role in tumorigenesis and possibly tumor progression of head and neck squamous cell cancer. Further exploration of Ubc9 in head and neck cancer is warranted. Significance Ubc9 expression in SCCHN LNM can increase the sensitivity of diagnosis in the primary site as well as in suspected lymph node metastases. Early and accurate diagnosis of LNM can potentially improve regional control of the disease. Support Part of the study was supported by a grant from SIU School of Medicine.