Gene Therapy for Cancer

A quarter of a century has passed since the expected realization of "Conquering cancer in the 21st century" due to advances in pharmaceuticals and medical technology. However, the effectiveness of treatments for malignant tumors, especially refractory cancers, remains inadequate and is difficult to achieve with conventional treatment methods alone. For example, there are high rates of metastasis and residual recurrence following surgical treatment, while chemotherapy and radiotherapy all too quickly lead to disease resistance, and their side effects significantly reduce patients’ quality of life. Under such circumstances, gene therapy products targeting cancer are some of the most highly desired therapies worldwide. The advantages of these innovative treatments are their clear mechanism of action and clinical efficacy based on molecular pathology. Several gene therapies have been approved for hematologic tumors and have shown dramatic therapeutic effects. On the other hand, the efficacy of gene therapies against solid tumors remains limited and improving their therapeutic efficacy remains a major challenge. In this review, we report the background and current status of gene therapy for cancer. In addition, oncolytic virus therapy and CAR-T cell therapy, which have the potential to be curative and are undergoing research and development, will be introduced in detail.