“Hybrid” was born from a sociological research and a theoretical reflection undertaken during the field investigation at the Regina Elena National Cancer Institute in Rome between 2017 and 2019. Hybridization, to which the book refers several times, indicates the mixture of heterogeneous elements and, in the specific case, refers to the process that is activated when biomedical categories enter the field of everyday life. The case of breast cancer is emblematic in that the large investments in oncology and the growing emphasis on prevention in public discourse correspond to a density of experience, of illness and of gender, perhaps without equal. Whatever emerges is that when genetic risk, body care and improvement techniques, social representations enter the field of biographical choices, the process of hybridization between nature and culture, between human and non-human assumes uncertain boundaries and that deserve a deeper theoretical and empirical study. The predilection, of Actor Network Theory background, to follow cancer in its complexity made possible to meet the women interviewed, with their assembled, disfigured, cybernetic bodies, with BRCA genes and DNA strands, deepening elements of history of medicine, analyzing the social representations and the ambivalent activism of the survivors.