RPMI-8226 (myeloma) and SK-MEL-5 (melanoma) showed rapid EtBr uptake in response to agonist stimulation (Fig. 1a, b), which was inhibited by pre-incubation with P2X7-specific inhibitors A438079 and A740003 (Fig. 1c, d). Here, P2RX7 is linked to plasma cell myeloma.