With advances in the understanding of characteristics of molecules, specific antigens on the surface of hematological malignant cells were identified and multiple therapies targeting these antigens as neoplasm treatments were developed. Among them, chimeric antigen receptor (CAR) T-cell therapy, which got United States Food and Drug Administration (FDA) approval for relapsed/refractory (r/r) diffuse large B-cell lymphoma (DLBCL) as well as for recurrent acute lymphoblastic leukemia (ALL) within the past five years, and for r/r mantle cell lymphoma (MCL) this year, represents one of the most rapidly evolving immunotherapies. Nevertheless, its applicability to other hematological malignancies, as well as its efficacy and persistence are fraught with clinical challenges. Currently, more than one thousand clinical trials in CAR T-cell therapy are ongoing and its development is changing rapidly. This review introduces the current status of CAR T-cell therapy in terms of the basic molecular aspects of CAR T-cell therapy, its application in hematological malignancies, adverse reactions during clinical use, remaining challenges, and future utilization.

Immunotherapy, including chimeric antigen receptor (CAR) T-cell therapy, immune checkpoint inhibitors, cancer vaccines, and dendritic cell therapy, has been incorporated as a fifth modality of modern cancer care, along with surgery, radiation, chemotherapy, and target therapy. Among them, CAR T-cell therapy emerges as one of the most promising treatments. In 2017, the first two CAR T-cell drugs, tisagenlecleucel and axicabtagene ciloleucel for B-cell acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL), respectively, were approved by the Food and Drug Administration (FDA). In addition to the successful applications to hematological malignancies, CAR T-cell therapy has been investigated to potentially treat solid tumors, including pediatric brain tumor, which serves as the leading cause of cancer-associated death for children and adolescents. However, the employment of CAR T-cell therapy in pediatric brain tumors still faces multiple challenges, such as CAR T-cell transportation and expansion through the blood–brain barrier, and identification of the specific target antigen on the tumor surface and immunosuppressive tumor microenvironment. Nevertheless, encouraging outcomes in both clinical and preclinical trials are coming to light. In this article, we outline the current propitious progress and discuss the obstacles needed to be overcome in order to unveil a new era of treatment in pediatric brain tumors.

Background: Multiple myeloma (MM) is known for its immune disturbance and patients suffering from MM are thus vulnerable to opportunistic infections, including herpes zoster (HZ). As HZ infection remarkably affects patients' quality of life and poses huge economic burdens on the health system, we aim to identify the risk factors of HZ infection and evaluate the effects of different dosages, types, and durations of anti‐HZ prophylaxis drugs to prevent HZ infection.Methods: 551 MM patients at Taipei Veterans General Hospital in Taiwan between January 1, 2009 and August 31, 2021 were restrospectively analyzed. The patients' baseline characteristics were recorded. The primary endpoint of the study was the incidence of HZ infection among the studied patient population. Due to the lack of cost coverage from Taiwanese public health insurance on HZ prophylaxis drugs, the use of anti‐HZ drugs mainly depends on physicians' preferences and patients' choices.Results: In our study, prophylaxis was given to 283 of the patients. In the multivariate analysis, we included non‐prophylaxis, age ≥ 60, corrected serum calcium ≥12 mg/dl, serum creatinine ≥2 mg/dl, serum β2‐microglobulin ≥5500 mg/L, autologous stem cell transplant (SCT), and allogeneic SCT for analysis. Our results demonstrated that the non‐prophylaxis group (HR: 2.37, 95% CI 1.57–3.57) and patients receiving autologous SCT (HR: 2.22, 95% CI 1.28–3.86) and allogeneic SCT (HR: 5.12, 95% CI 1.13–23.22) had higher risk of HZ infection. The difference in dosage and types of anti‐HZ drugs showed similar protective effects. In patients who stopped anti‐HZ prophylaxis before active cancer‐related treatment, a higher risk of getting HZ infection compared to the corresponding group was also observed (adjusted HR 3.09, 95% CI 1.35–7.07, p = 0.008).Conclusions: We concluded that MM patients should receive HZ prophylaxis drugs while receiving active cancer‐related treatment. Patients receiving SCT are also at high risk of getting HZ infection, even under prophylaxis.