PTEN and neoplasm: The two main pathways related to the NTPDase5/mt-PCPH activity are the mTOR and the PI3K/PTEN signaling pathways, which are directly related, since the inhibition of PTEN results in a PI3K and consequent AKT overactivation, which in turn regulates the growth of tumor cells by different signaling pathways, one being its effect on mTOR (Figure 2).