Association of tissue factor expression in squamous cell head and neck carcinomas with well-differentiated tumors.

e16022 Background: Tissue factor (TF) is a glycoprotein that initiates coagulation when complexed with factor VIIa. High levels of TF expression have been found in many cancers and correlated with tumor aggressiveness. TF has been shown to be expressed in head and neck squamous cell carcinomas (HNSCC) but the role of TF on cell function and prognosis are not known. The epidermal growth factor receptor (EGFR) is overexpressed in many HNSCC and EGFR and TF expression are highly correlated in some tumor types. Our goal was to correlate the expression of TF and EGFR in HNSCC with tumor cell differentiation and prognosis. Methods: Twenty biopsy specimens of squamous cell head and neck carcinomas were studied. Immunohistochemistry for TF, EGFR, and p16 was performed. Cases were scored based upon the staining intensity of tumor cells using a semiquantitative scale as negative, weakly (+), moderately (++) or strongly (+++) positive. Results: The tumor stages ranged from T1N0 to T4N3. Of the 20 specimens, 5 were well differentiated, 12 were of moderate differentiation, and 3 were poorly differentiated. Median survival was 23 months, median follow-up 73 months. TF was expressed in 75% (15/20) of tumors at varying levels. Moderate TF expression was found in 6 specimens, and 9 showed weak expression. None of the poorly differentiated tumors expressed TF, and there was a definite negative correlation between TF expression and tumor differentiation (Pearson r=--0.747, p=0.0002). There was no association between TF expression and survival (Log-Rank 0.3115, p=0.8558). All of the tumors analyzed expressed EGFR and there was no correlation between TF expression and EGFR expression. Overall, 25% (5/20) of tumors expressed p16, suggesting human papilloma virus infection. Conclusions: Results from this retrospective study indicate that well differentiated HNSCC express higher levels of TF than poorly differentiated tumors and that TF and EGFR expression are not tightly linked. Moreover, unlike other cancer sites, HNSCC TF expression did not appear to worsen overall patient survival, and was actually associated with more well-differentiated tumors.