CXCL12 and familial pancreatic carcinoma: Furthermore, as EGFR is upstream of the RAS pathway, loss of EGFR may not affect activation of RAS/RAF/MEK/ERK introduced by mutant KRAS. Notably, one study showed that KRAS pathways coordinate the transduction of CXCL12/CXCR4/CXCR7 and influence growth of pancreatic cancer [47].