Immune cells in residual disease and recurrence.

Tumor recurrence following potentially curative therapy constitutes a major obstacle to achieving cures in patients with cancer. Recurrent tumors frequently arise from a population of residual cancer cells - also referred to as minimal residual disease (RD) or persister cells - that survive therapy and persist for prolonged periods prior to tumor relapse. While there has been significant recent progress in deciphering tumor-cell-intrinsic pathways that regulate residual cancer cell survival and recurrence, much less is known about how the tumor microenvironment (TME) of residual tumors impacts persister cancer cells or tumor recurrence. In this review, we highlight recent studies exploring the regulation and function of immune cells in RD and discuss therapeutic opportunities to target immune cells in residual tumors.