PROJECT SUMMARY/ABSTRACT Persons with HIV (PWH) experience worse cancer outcomes compared to those not living with HIV. Numerous social and structural determinants of health (SDOH) have been identified for PWH, and for cancer care, including cultural barriers, stigma, insurance status, healthcare access, the built environment, and more. HIV stigma is associated with suboptimal engagement in care, differential cancer risk, and prevention behaviors. Further, the cumulative burden of living with HIV compounded by a cancer diagnosis can negatively affect clinical outcomes. Few studies have explored the perspectives of PWH and cancer, limiting development of interventions designed to improve the treatment experience and outcomes. Additionally, PWH from the most marginalized groups who are diagnosed with cancer have risk factors for poor health outcomes. Gender and sexual minorities as well as people who are Black or Latinx tend to have less access to health care, poorer quality of care and general health outcomes. However, little is known about how SDOH risk factors intersect and affect HIV cancer outcomes. We seek to improve understanding of SDOH including patient, provider, and system-level drivers of cancer disparities among PWH to identify the most critical and actionable areas for intervention. Our specific aims are to (1) Explore HIV care engagement, and the cancer prevention, diagnosis, and treatment experiences of PWH diagnosed with cancer, focusing on (a) health care engagement and treatment adherence prior to and after cancer diagnosis and (b) the roles of social stigmas (e.g., HIV stigma, cancer stigma, racism, homophobia) in cancer screening and diagnosis; (2) Examine associations of SDOH with the cancer diagnosis, treatment and outcomes among PWH receiving care or follow-up of cancer at UCSD. This will be accomplished using a mixed methods approach including (1) Semi-structured qualitative interviews conducted with consenting UCSD patients undergoing cancer care or monitoring to better understand the experience of PWH receiving cancer care and (2) quantitative methods to identify SDOH factors associated with health outcomes in UCSD’s cohort of PWH and cancer via EMR abstraction coupled with a short quantitative survey. Identified factors will be associated with cancer outcomes including stage at diagnosis, engagement in cancer therapy, remission, and survival rates. Accomplishment of these aims will contribute to understanding the social and structural determinants of cancer care outcomes among PWH and identify actionable areas for future interventions aimed at mitigation and elimination of cancer disparities in PWH.