Late-stage tertiary lymphoid structures in hepatocellular carcinoma treated with neoadjuvant immune checkpoint blockade [scRNA-seq]

Tertiary lymphoid structures (TLS) are associated with improved response in solid tumors treated with immune checkpoint blockade (ICB), but understanding of their clinical significance and the circumstances of their resolution remains incomplete. Here, we found that in hepatocellular carcinoma (HCC) treated with neoadjuvant immunotherapy, high intratumoral TLS density at the time of surgery is associated with pathologic response and improved relapse free survival. In areas of tumor regression, we further identified a non-canonical involuted morphology of TLS marked by dispersion of the B cell follicle, persistence of a T cell zone enriched for T cell-mature dendritic cell interactions, and increased expression of T cell memory markers. Collectively, these data suggest that TLS may serve be both a prognostic and predictive marker of response to immunotherapy in HCC and suggest a functional role for late-stage TLS T cell memory formation after elimination of viable tumor.