Familial Nasopharyngeal Carcinoma 6

30 Q-T. Le and J. J. LuFig. 3.1. ErbB/HER Signaling Network (Pathway diagram reproduced courtesy of Cell Signaling Technology, Inc. [www.cellsignal.com])(Vermorken et al. 2008). Since the pathogenesis andbiological behavior of NPC are substantially differentfrom other head and neck malignancies, it is notsurprising that NPC was not included in the abovementionedtrials and the results of these studiestherefore cannot be directly extrapolated to NPC.3.2.4EGFR in Nasopharyngeal CarcinomaSimilar to SCCHN, overexpression of EGFR in NPC isquite frequent and has been reported to be as high as80% in primary tumor biopsies (Sheen et al. 1999;Chua et al. 2004; Soo et al. 2005; Pan et al. 2008).Similarly, clinical studies have shown that EGFRoverexpression is a negative prognostic factor forNPC as for other SCCHN: The expression of EGFR(as well as that of cytoplasmic VEGF and COX-2) hasbeen shown to correlate with tumor AJCC staging inpatients with stage II to IV NPC, with higher expressionfound in more advanced stage tumors (Zhenget al. 1994; Pan et al. 2008). Overexpression of EGFRwas also shown to be an independent prognostic factorfor treatment outcome in patients with locoregionallyadvanced NPC. In a prospective study fromthe Prince of Wales Hospital in Hong Kong, strongpretreatment EGFR expression in the primary tumorby immunohistochemical (IHC) staining was significantlylinked to shorter overall survival and time to