Oropharyngeal squamous cell carcinoma (OPSCC) is a prevalent subtype of head and neck cancer representing one of the largest diagnosed malignancies worldwide. A distinct subtype of OPSCC induced by Human Papilloma Virus (HPV) is well known to favor beneficial clinical outcomes in cancer treatment compared to HPV-negative OPSCCs. However, HPV-positive OPSCCs in the context of immunotherapy remains unclear, as no distinct benefits are observed in clinical trials. In this study, we performed single-cell RNA and T cell receptor sequencing analyses of 20 tumor samples to dissect the cellular and molecular factors associated with viral infection and immunotherapy outcome. We found significantly higher transcriptional diversity of malignant cells among non-responders to immunotherapy, regardless of HPV infection status. This finding suggests heterogeneity of malignant cells negates immunotherapy response in HPV-positive OPSCCs. We also observed a significantly larger proportion of CD4+ follicular helper T cells (Tfh) in HPV-positive tumors, potentially due to enhanced Tfh differentiation. Most importantly, CD8+ resident memory T cells (Trm) with elevated KLRB1 (encoding CD161) expression showed significant association with dampened antitumor activity in HPV-positive OPSCC patients, which may explain their clinical heterogeneity. Notably, all HPV-positive patients, whose Trm presented elevated KLRB1 levels, showed low expression of CLEC2D (encoding the CD161 ligand) in B cells, which may reduce tertiary lymphoid structure activity. Validation in an independent cohort confirms enhanced tertiary lymphoid structure activity in HPV-positive OPSCCs. Immunofluorescence of HPV-positive tumors treated with immune checkpoint blockade confirmed an inverse correlation between the density of CD161+ Trm and changes in tumor size. These results suggest that targeted inhibition of CD161 in Trm may augment immunotherapy efficacy in HPV-positive oropharyngeal cancers.

Citation Format: Junha Cha, Dahee Kim, Gamin Kim, Jae-Won Cho, Euijeong Sung, Seungbyn Baek, Min Hee Hong, Chang Gon Kim, Nam Suk Sim, Hyun Jun Hong, Jung Eun Lee, Martin Hemberg, Seyeon Park, Sun Ock Yoon, Sang-Jun Ha, Yoon Woo Koh, Hye Ryun Kim, Insuk Lee. CD161+ TRM cells counteract HPV-associated clinical benefits in oropharyngeal cancer immunotherapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2023 Oct 1-4; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Immunol Res 2023;11(12 Suppl):Abstract nr B032.