International audienceFrance now counts nearly 400,000 new cancer cases per year. Yet, even though this epidemic is shaped by strong inequalities, the role of work as a cause of cancer remains underacknowledged, if not ignored. In the GISCOP 84 cohort study on blood cancer patients taken care of at Avignon Central Hospital, each cancer is considered as a "sentinel event" giving access to the patients’ past (and present) occupational exposures to carcinogens, as well as to the obstacles to – and levers of action for – the prevention of occupational cancers and their compensation as occupational diseases. This article presents the GISCOP approach and the type of knowledge it produces. It also analyzes the institutional resistances this action...