Connected to this, intriguingly, we observed the loss of PRR expression in local and distant metastases compared to the primary tumours, which could suggest that although PRR seems to have an important role in the development of metastases, once it is generated, the adaptation of CRC cells in the new microenvironment might prioritise alternative signalling pathways beyond PRR-related ones (Malladi et al., 2016). The gene discussed is ATP6AP2; the disease is colorectal carcinoma.