This paper is based on an ethnographic case study drawn from 16 months of fieldwork with families and young people going through cancer diagnosis and treatment in Oakland, California. The paper explores the intersection of cancer patienthood and racial formation, emphasizing the entanglement of biogenetic and sociogenetic processes. The paper shows how, as cancer-inflicted bodies move through the world, they are subjected to sociohistorically produced racial classifications that can be deployed in destructive, humiliating, and stress-inducing ways. Yet racialization can also occur in a more affirming, supportive, and resistant register—for example, through participation in community-based cancer advocacy efforts. The paper emphasizes three points of intersection between cancer patienthood and racial formation: 1) the racialization of oncologically transformed bodies; 2) the racialization of attempts to raise cancer awareness; and 3) the racialization of the expression of negative emotions in healthcare interactions. In doing so, the paper shows that racialization is a fundamental sociogenetic process that is entangled with the biogenetic processes that cancer scientists describe as “oncogenesis.” Entangled biogenetic and sociogenetic processes constitute the existential trajectories that cancer patients and their families inhabit.