Sporadic cases, which represent the vast majority of PDAC, are associated with activation of the KRAS oncogene (>90% of cases) and inactivation of the INK4A/ARF (>80% of cases), TP53 (>50% of cases) and SMAD4/DPC4 (>50% of cases) tumor suppressors. The gene discussed is KRAS; the disease is neoplasm.