KRAS and cancer: Serpin family I member 2 (SERPINI2), a tumor suppressor gene downregulated in PDAC and other cancers (Wehr et al., 2011; Bergeron et al., 2010), and microRNA mir-217 (MIR217), a potential tumor suppressor gene in PDAC (Zhao et al., 2010), which targets KRAS expression, were among the most underexpressed genes in the OCM tumors (Fig. 5A).