Review of Costimulatory Molecule B7 Family and Its Role in Esophageal Cancer

The incidence of esophageal cancer accounts for the ninth-highest of malignancy incidence in the world. Its prevalence and distributions are relative regionalism. China is a high-risk area of esophageal cancer. Although varieties of therapeutic strategies, including conventional surgery, chemotherapy, radiotherapy and immunotherapy, and combination of these therapies, have been improved in the treatment for esophageal cancer patients in recent decades, the overall treatment efficacy remains disappointing. With the development of tumor immunology and the gradually in-depth understanding of tumor, it was found that the occurrence and progression of esophageal cancer are closely related to the immune depressive function in patients. How to stimulate anti-tumor immune response and kill residual cancer cells in vivo becomes the key to enhance the treatment efficacy of esophageal cancer and prevent the recurrence and metastasis. Tumor-infiltrating T cells (TIL) are the main effector cells to mediate anti-tumor immune response and play a very important role in anti-esophageal immunity. However, abnormal expression of its surface costimulatory molecules often lead to the anergy of TIL, or even suppress other immune cells in tumor immune responses and then help tumor cells evade the immune surveillance. Therefore, this article reviews the expression and clinical significance of costimulatory molecules B7 family in esophageal cancer, in order to provide experimental evidence and theoretical support for future development of immunotherapy strategies for esophageal cancer .