In recent years, STS scholars have analyzed the emergence of a novel kind of patient group characterized by a “partnership model” and “evidence-based activism” (Akrich, Rabeharisoa, Callon). The present contribution builds on this line of work by focusing on the emergence of cancer patient groups such as ROS1ders, EGFR Resisters, and ALK-positive, whose identity is grounded in sharing a particular genomic variant within or across different types of cancer. We examine how these groups have established close links with oncologists, leading to the establishment of distinctive forms of biomedical innovation. Given the rarity of some molecularly defined cancers, these groups often have members from different countries and continents and resort to social media to develop their activities both at the national and international levels. Our investigation resorted to qualitative and quantitative approaches. Using a standardized list of hashtags, i.e., “[type of cancer]sm” (e.g., #bcsm for breast cancer social media, etc.), we created a database of tweets. We used a supervised learning approach to classify the source of tweets as originating from patient groups, oncologists, media organizations, and the industry. In addition to characterizing the dynamics of these groups (retweets, replies, chats), we explored the content of tweets through their semantic embedding. In parallel, we interviewed several patient advocates and oncologists who are particularly active on social media. According to our preliminary results, oncogene-focused patient groups self-define as research advocates, their activities evolving in parallel with the evolving understanding of cancer(s). As recognized components of the precision oncology collective, they accelerate research on their own diseases and circulate information via hybrid networks. They contribute to establishing the required infrastructure (e.g., cell-lines, patient-derived xenografts, and real-world date) and design collaborative research projects for developing and testing new drugs.