P2RX7 and head and neck cancer: Also supporting a role for P2X7 receptor in tumor growth is the fact that many types of cancer such as leukemia (98, 105, 106), melanoma (107), neuroblastoma (108), pancreatic adenocarcinoma (109), esophageal carcinoma (110), breast (111), prostate (112), thyroid (113), and head and neck cancer (114) showed an increased expression of P2X7 receptor.