P2RX7 and neoplasm: P2X7 is detected in fewer samples than nfP2X7 (44% average positive tumours for nfP2X7 against 18% for P2X7) with higher nfP2X7 expression observed in bladder, kidney, colorectal and lung cancer including all of the 18 squamous non-small cell lung cancer (NSCLC) samples tested (Fig. 7c).