Updated project metadata. Chemoresistance hampers the treatment of patients suffering from pancreatic ductal adenocarcinoma (PDAC). The present study aimed to evaluate the proteome and phosphoproteome of gemcitabine-sensitive and -resistant PDAC cells to identify novel targets and predictive biomarkers.The oncogenic capabilities of sensitive and resistant PDAC cells were evaluated in vitro and in vivo. Cultured cells were subsequently analysed by label-free mass spectrometry. Differential proteins and phosphopeptides were evaluated for Gene Ontology and predictive and / or prognostic biomarker potential by immunohistochemistry of tissue microarrays (TMAs). Differential analyses showed that resistant proteins are associated with membrane organization and microtubule regulation. Importantly, resistant cells displayed an increased sensitivity for paclitaxel treatment in vitro (p < 0.001) and nab-paclitaxel had a strong anti-tumour efficacy in vivo. Microtubule-associated protein 2 (MAP2) was found to be highly upregulated and phosphorylated in resistant cells. The identified resistance marker MAP2 emerged as a novel prognostic marker in PDAC patients treated with gemcitabine.