Firstly, an inflammatory microenvironment has long been regarded as a hallmark of cancer.120 Secondly, tumour microenvironment is rich in ATP and adenosine.121 Thirdly, a variety of purinergic receptors are expressed in a wide range of tumour types.122 Moreover, ATP and adenosine are critical for the energy metabolism of cancer cells. This evidence concerns the gene P2RX5 and cancer.