The role of bone marrow microenvironment on CAR‐T efficacy in haematologic malignancies

Abstract In recent years, chimeric antigen receptor‐T (CAR‐T) cell therapy has emerged as a novel immunotherapy method. It has shown significant therapeutic efficacy in the treatment of haematological B cell malignancies. In particular, the CAR‐T therapy targeting CD19 has yielded unprecedented efficacy for acute B‐lymphocytic leukaemia (B‐ALL) and non‐Hodgkin's lymphoma (NHL). In haematologic malignancies, tumour stem cells are more prone to stay in the regulatory bone marrow (BM) microenvironment (called niches), which provides a protective environment against immune attack. However, how the BM microenvironment affects the anti‐tumour efficacy of CAR‐T cells and its underlying mechanism is worthy of attention. In this review, we discuss the role of the BM microenvironment on the efficacy of CAR‐T in haematological malignancies and propose corresponding strategies to enhance the anti‐tumour activity of CAR‐T therapy.