Stress keratin 17 and CD4/8 ratio as prognostic markers in HIV-related anogenital squamous cell precancers and cancers ABSTRACT Scientific Rationale: Despite the decrease in mortality people living with HIV (PLWH) due to combination antiretroviral therapy, anogenital human papillomavirus (HPV)-related squamous dysplasia and cancer are more common among PLWH.1–9 There is a lack of prognostic markers to risk stratify anogenital squamous dysplasia and cancer among PLWH. There is a critical need to identify prognostic markers (circulating blood markers and/or epithelial markers) to predict disease development and progression particularly in PLWH. Hypothesis: Our central hypothesis is that K17 expression may correlate with circulating low CD4/CD8 T cell ratio, reflective of a suppressive tumor microenvironment, in HIV-associated precancers and cancers of the anogenital tract, and, therefore, predict prognosis. Project Design: In Aim 1, we will test whether a biomarker we found upregulated in response to HPV infection in preclinical models (keratin 17; K17) correlates with progression, regression and/or prognosis among PLWH with anogenital precancers and cancers. We will use immunohistochemistry as well as cutting edge spatial single cell multiplex imaging to profile the tumor microenvironment and spatial relationships in AIDS and Cancer Specimen Resource (ACSR) tissue microarrays, and our own tissue microarrays among anogenital dysplasia and cancers from HIV+ and HIV- patients. In Aim 2, we will determine if circulating CD4/8 T cell ratio and/or other immune cell subsets predict clinical outcomes in anogenital precancers and cancers. Relevance: Our study will test two potential markers of prognosis of anogenital disease among PLWH and better define the tumor microenvironment that allows for disease progression in these patients. This is a collaborative P30 Administrative Supplement Application from Drs. Evie Carchman, Megan Fitzpatrick, Huy Dinh, Nathan Sherer, Lisa Barroilhet, and Paul Lambert. Our multidisciplinary team includes a junior gynecologic pathologist with experience in HPV molecular virology and dysplasia studies among PLWH with HIV/AIDS (Co-Project leader: Fitzpatrick), a colorectal surgeon with expertise in the treatment of various HPV-associated anogenital diseases and expertise in use of mouse anal cancer preclinical models (Co-Project leader: Carchman), a tenured gynecologic oncologist with clinical and research experience in detection and treatment of HPV-related gynecologic cancers (Barroilhet), a computational biologists with track record in evaluating complex tumor immune microenvironments in multiple cancer types, including HPV-related cancers (Dinh), a researcher with expertise in HIV (Sherer), and a senior expert in HPV infection and HPV-related cancers whose lab has developed multiple preclinical mouse models for anogenital cancer (Lambert).