REL and head and neck squamous cell carcinoma: Real-time qPCR reveals that acidic-pepsin expresses lower mRNA levels of the analyzed NF-κB transcriptional factors, RELA(p65) and c-REL [18–20,28,31], anti-apoptotic bcl-2 [21,32], cell signaling TNF-α [28–30,43], oncogenic STAT3, an important molecule involved in NF-κB related tumorigenic phenotypes [20,23–25,44], EGFR, a common genetic event in HNSCC [20,22,23], and wnt5α, upregulated in epithelial to mesenchymal transition [27].