Regarding the current evidence, the PGRN-mediated regulation of cancer cell proliferation is mediated through several signalling pathways, such as PI3K/AKT, protein kinase C (PKC), c-Myc, ERK1/2 and another MAPK, where some data support the view that PGRN modulates the activity of cyclin-dependent kinase 4 (CKD4) and levels of cyclin B and cyclin D1 [77,78,79]. The gene discussed is GRN; the disease is cancer.