NPs have been shown to inhibit tumour growth in several in vitro and in vivo studies,162–165 nevertheless, these associations should be interpreted with caution, as some malignant cells are also able to produce NPs, questioning generalizability of tumour-inhibitory effects of NPs.166,167 In addition, it is noteworthy that in principle neprilysin inhibition also increases the availability of factors other than NPs that might influence cancer cell biology.168 The effects of these substrates should also be considered in future investigations addressing the effects of ARNI on cancer. This evidence concerns the gene MME and cancer.