PFN1 and neoplasm: The authors mostly focused on the downregulation of calreticulin and the upregulation of profilin 1, as these variations are associated with tumor aggressiveness, but they also reported an upregulation of PKM2, i.e. the embryonic form of pyruvate kinase: this isoform is frequently re-expressed in tumor cells, and gives them a proliferative advantage in hypoxic conditions [31].