[Molecular characterisation defines several subtypes of pancreatic ductal adenocarcinoma]

Multi-omics high throughput analyses lead to the description of multiple molecular subtypes of pancreatic adenocarcinoma with major prognostic impact for most of them. There is no consensual multilevel integrative classification yet like in colon or breast cancers. Genomic classifications have identified a tumor subtype (15% of the patients) with deficient homologous DNA repair-system leading to increase sensitivity to platinum-based therapies and possibly to PARP inhibitors and immunotherapies. Transcriptomic classifications are still debated but all have identified an aggressive subtype with a very poor prognosis, presumably unfit for a surgical approach. Finally, approaches based on metabolomic or proteomic profiling have identified subtypes with a particular sensitivity to compounds targeting the hallmarks metabolomics or oncogenic pathways of each subtype. These classifications were mostly based on tumor cell but the micro-environment is also very heterogeneous and several types of stroma will be described soon. Subtype determination in daily practice remains a major challenge as most technologies used to build these classifications are very expensive, requires dedicated bio-informatics analysis pipelines and are not adapted to routine samples that are mostly formal in fixed paraffin embedded biopsies, in which tumor cells are highly contaminated by the cell from the microenvironment and the clot.