CD8+ T Cell Dysfunction in Tumor-Draining Lymph Nodes: A Hallmark of Tumor Immune Escape That May Arise Early During the Course of Cancer Progression

Tumor-draining lymph nodes function paradoxically not only as key sites for the priming and coordination of anti-tumor CD8+ T cell responses but also as regional hubs through which invading tumor cells can seed distant metastases. The quality of tumor-specific CD8+ T cells elicited at this site is therefore a critical determinant of the outcome of anti-tumor immunity and cancer progression. Recent studies have demonstrated the significance of CD8+ T cell dysfunction within tumor-draining lymph nodes, highlighting it as an important means of tumor immune escape that may arise early in the course of cancer progression. This review aims to bring attention to emerging data on this topic, with particular focus given to the implications that lymph-node-resident CD8+ T cell dysfunction has both for cancer immunotherapy and for pre-metastatic niche formation during early stages of cancer progression.