MSLN and cancer: Mesothelin (MSLN) is only expressed, at a low level, in healthy mesothelial tissues (pleura, peritoneum, pericardium), and is also highly expressed in several human cancers, notably in cancers characterised by aggressive phenotypes and poor prognoses such as mesothelioma, pancreatic, lung, ovarian cancers, acute myeloid leukaemia or triple negative breast cancers (4, 5).