Preclinical studies in breast, lung, colon, prostate, and pancreatic cancer showed that CXCR4high tumors have enhanced metastatic potential compared to CXCR4low, and plerixafor as a monotherapy or combined with chemotherapy successfully reduces tumor growth and metastases through inhibition of the extracellular signal-regulated kinase 1/2 (ERK1/2) and AKT pathways [214,216,217,218,219,220,221]. This evidence concerns the gene MAPK3 and familial pancreatic carcinoma.