MAPK3 and head and neck squamous cell carcinoma: In head and neck squamous cell carcinoma (HNSCC), it has been reported that P2Y2 receptor-activated ERK1/2 signaling promotes proliferation of CAL27 cells, and further blockade of the P2Y signaling via a specific antagonist and genetic knockout reduced UTP-induced CAL27 proliferation in vitro [33].