In conclusion, although emerging evidence suggests a rationale for targeting P2Y12R to constrain tumor progression, metastasis development, and pain and to potentiate the responses to conventional therapies, a definitive evidence of the anticancer effect of P2Y12R antagonists is lacking. Further studies of basic and clinical research are urgently needed in this setting to put a final word on the role of the purinergic signaling in cancer development and metastasis.