Bone Morphogenetic Protein 6 Expression in Oral Cavity Squamous Cell Cancer is Associated With Bone Invasion

Objectives/HypothesisTo evaluate bone invasion, survival, and expression of bone morphogenetic protein-6 (BMP-6) in oral cavity cancer in the context of known biomarkers indicative of poor prognosis. Study DesignMolecular expression study combined with retrospective chart review of corresponding patients at a tertiary care center. MethodsBetween 2000 and 2009, a total of 197 patients underwent resection for oral cavity squamous cell carcinoma. Of these, 30 pathologic specimens were chosen for further molecular analysis. These 30 patients were separated into three groups (10 per group) based on American Joint Committee on Cancer (AJCC) staging and staging based on size alone (T-AJCC/(SIZE)). The first group consisted of tumors staged as T-2/(2) based on size less than 4 cm and that had no evidence of bone invasion. The T-2/(4) group consisted of tumors that were upstaged from T-2 based on bone invasion. The T-4/(4) group consisted of tumors that were large with and without bone invasion. The expression of extracellular matrix metalloproteinase inducer (EMMPRIN), BMP-6, and epidermal growth factor receptor (EGFR) was examined using immunohistochemistry techniques. Patient demographics, tumor characteristics, survival, and recurrence were compared. ResultsAverage follow-up was 21 months. Expression of BMP-6 was significantly higher in the T-2/(4) cohort (tumor less than 4 cm with bony invasion) than the larger tumors without bone invasion (T-4/(4) cohort, P=.05). In addition, increased BMP-6 expression correlated with aggressive behavior in the smaller tumors. Furthermore, increased EGFR expression positively correlated with increased levels of BMP-6. ConclusionsIncreased expression of BMP-6 in oral cavity cancer may affect bone invasion. Level of EvidenceN/A. Laryngoscope, 123:3061-3065, 2013