The “Cancer” scientific axis brings together 17 teams involved in the study of the molecular and cellular mechanisms favoring the development of cancers in the context of their microenvironment. The fundamental and medical research programs are based on strong interactions with the medical, surgical and biology departments involved in the management of patients with endocrine tumors, blood diseases, digestive, pulmonary or skin cancers, or sarcomas in the University Hospital group AP-HP.Centre-Université Paris Cité, and with the Department of Medicine and Health of Université Paris Cité. The teams are supported by future investment programs such as the CARPEM integrated cancer research site, the “Who Am I” and “GR-Ex” LabEx, and by European research networks (H2020, COST shares). The major research themes relate to the study of (i) the mechanisms of genetic instability, linked to DNA replication and repair, (ii) the epigenetic, genetic, transcriptional and post-transcriptional mechanisms that deregulate gene expression, (iii) normal and cancer stem cell biology, (iv) metabolic and signalling abnormalities and their pharmacological targeting, (v) lymphoid and myeloid immune microenvironment, and mesenchymal and vascular microenvironment. Our research also aims to study the mechanisms of action of immunotherapies targeting immune checkpoints and to develop new therapeutic strategies such as CAR-T cells.