RIPK2 and head and neck squamous cell carcinoma: It is known that REEP6 enhances the activation of IL-8/CXCR1 [21] and IL-8/CXCR1 via the nucleotide binding oligomerization domain containing 1 (NOD1)/receptor-interacting-serine/threonine-protein kinase 2 (RIP2) signaling pathway, which is important for head and neck squamous cell carcinoma cell proliferation [34].