359P Integrative molecular and spatial analysis of intratumoral tertiary lymphoid structures: Insights into immunotherapy response

Intratumoral tertiary lymphoid structures (TLS) have been associated with improved outcomes and response to immunotherapy in various cohorts of patients with cancer. Primarily, mature TLSs (mTLSs) developing germinal centers serve as sites for local antigen presentation by dendritic cells, supporting the generation of tumor-targeting CD8+ effector memory T cells. In line with this notion, a further understanding of the key quantitative and qualitative differences in mTLS formation and progression in immune checkpoint inhibitor (ICI)-responsive and ICI-resistant neoplasms may guide the development of alternative therapies in poorly responsive carcinomas.