SOS1 and familial pancreatic carcinoma: The guanine-nucleotide-exchange factors SOS1 and SOS2 (herein referred to as SOS1/2), which activate WT Ras, function downstream of EGFR and other receptor tyrosine kinases but also independently of EGFR through allosteric interaction of SOS1/2 with oncogenic K-Ras, which contributes to pancreatic cancer cell growth (Jeng et al., 2012).