The professional setting still constitutes a space in which bodily engagement may have deleterious effects. This is particularly true for the most precarious workers. This thesis proposes to explore one of its consequences, that of occupational cancer. Occupational cancer socially relatively invisible socially, we will study its repercussions both on an institutional and on a profane level. The different logics which underlie the categorization are mobilized to found an analysis of the workers’ bodies, their bodily practice and the class relations in which they are engaged. Several levels of analysis are mobilized: a diachronic analysis of the category and the way in which it is elaborated and evolves and a synchronic analysis of the patients suspected, at a given moment, to be suffering from an occupational cancer. This latter also involves; the patient’s entourage (spouse and more broadly the territorial relational networks by which the patients obtain knowledge about the sites on which workers are exposed to toxic substances), associations and trade unions, administrative agents and doctors. My methodology is based on interviews with patients and/or their beneficiaries, administrative agents, doctors, and members of associations and trade-unions. I have also observed medical consultations, meetings of regional decisional bodies for the diagnosis of occupational illness and the open office hours and consultations of associations devoted to the recognition of occupational illness.This thesis is a contribution to the sociology of occupational cancers opened by the pioneering work of Annie Thébaud-Mony during the 1990s (Thébaud-Mony, 1991, 2003, 2006, etc.), and developed by researchers at the GISCOP93 laboratory (in particular: Anne Marchand, 2016 and 2018, Michelle Paiva, 2016, etc.) At the same time it is a contribution to the sociology of "blue-collar workers' bodies". Regarding the first field, I show how the category is reconfigured as it passes through medical, administrative, militant and domestic spaces. Its boundaries are played out in these spaces via the steps in the process of recognition, which include the victim’s claim, an individualization of the carcinogenic risk and the experience of illness. The (ex) worker comes to suffer from a triple injunction to be at once a good worker, a good patient and a good victim. In so far as the second field is concerned, I show how the work passes the boundaries of worker’s skin in a particular manner. The workers studied seem to resist committing their entire body to their work and its sequels, though the experience of illness cannot be seen to enter into a distinct class-inspired grammar. Thus, if the workers' collectives can sometimes serve as a resource, they have difficulty making sense of an experience that becomes individualized as work relationships are transformed and class rhetoric loses its public. However, it is sometimes the category, often operationalized by doctors and the workers’ bodies, that awakens identification to a precarious condition, suggesting a complex interweaving of power relationships with relation to this object.