Molecular pathology of intraductal papillary mucinous neoplasms of the pancreas: current understanding and perspectives on malignant progression

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are bona fide cystic precursor lesions to pancreatic ductal adenocarcinoma (PDAC), which is the cancer type with the most dismal prognosis. Since IPMNs are detectable by imaging, they offer a rare window of opportunity for early intervention for PDAC development. Despite their clinical visibility, the molecular pathogenesis of IPMNs remained incompletely understood, and no effective non-surgical therapeutic strategies have been established to date. In the past few decades, however, substantial progress has been made in elucidating their molecular pathology. Next-generation sequencing technologies demonstrated the comprehensive genetic mutation profile of IPMNs in the early 2010s. Elucidation of these mutation profiles enabled the establishment of genetically engineered mouse models, successfully recapitulating the natural development of human IPMNs and their progression to invasive cancer. Rapid evolution of "omics" technologies in recent years has facilitated the application of mass spectrometry, single-cell sequencing and spatial transcriptomics to IPMNs, significantly advancing our understanding of their pathophysiology. These techniques elucidated the changes in transcriptome, proteome, metabolome, microbiome, and tumor microenvironment associated with IPMN development and progression. This review summarizes current insights into the molecular and cellular landscapes of IPMN tumorigenesis, with particular emphasis on the mechanisms driving malignant progression.