NOD2 and head and neck squamous cell carcinoma: Stimulation of NOD1 and NOD2 was found to be protective in inflammation‐induced CRC,69, 70, 71, 80 whereas there was no straightforward answer as to whether activation of NOD1 in the stomach promotes or prevents the development of GC.72, 73, 74 Moreover, NOD1 was found to be upregulated in PC,79 HNSCC,77, 78 OSCC,76 and GC,73, 74 as opposed to certain studies that reported NOD1 downregulation in the cases of OSCC75 and GC.72 NOD2 was also found to be upregulated in GCs.74