Pancreatic adenocarcinoma, with an incidence/death ratio of 0.99, has the worst prognosis of all cancers. Risk factors associated with the sporadic form of pancreatic adenocarcinoma are unknown and less than 10% of patients receive curative treatment (surgery associated with radiation therapy or chemotherapy) with a low 5-year survival rate (10 to 20%). In more than 90% of patients, the tumor discovered at diagnosis is not resectable or has already metastasized. Thus, a better understanding of the etiology of pancreatic cancer is essential to identify new prognostic markers and new therapeutic targets. There is a wealth of data on the identification of genetic alterations associated with pancreatic cancer and their role in its development. This review will focus on the current knowledge of genetic alterations associated with two pancreatic lesions that can potentially evolve into pancreatic adenocarcinoma, Pancreatic Intraepithelial Neoplasia (PanIN) and Intraductal Papillary Mucinous Neoplasm (IPMN). These two lesions share a large panel of typical genetic alterations which are close to those found in pancreatic adenocarcinoma. A better understanding of these alterations may lead to therapeutic targets that could help prevent the progression of PanIN and IPMN to cancer.