Surgery, radiotherapy, and chemotherapy have always been the main treatment methods for malignant tumors. In recent years, with a deeper exploration of gene technology, the development of molecular targeted therapy and biotherapy has received great attention at home and abroad. Biotherapy combined with traditional treatments has achieved remarkable results in improving the quality of life and prolonging survival of patients, which has brought hope to patients with advanced cancer.

Biotherapy refers to the application of biological response modifiers, including all biological agents, chemical agents, and biotechnological methods to directly or indirectly inhibit tumor growth or reduce treatment-related adverse reactions. These modifiers can change the biological response of the body by immunity, gene expression, and endocrine or cell signal transduction pathways.

Biological therapy is divided into cell therapy and non-cell therapy, and currently, cell therapy is dominant, which includes four types.

1. Cytokine-induced killer (CIK) cells—"mechanized infantry" of cellular immunotherapy

With strong anti-tumor activity and non-restrictive tumor-killing advantages, CIK cells can be used in patients of any stage of tumor and are widely used internationally. This cell has a strong ability to accurately identify and kill tumor cells, especially for treatment after surgery or radiotherapy and chemotherapy. It can eliminate residual small metastatic lesions, prevent tumor cells from spreading and recurring, and improve the body's immunity.

2. Dendritic cells (DCs)—"signal corps " of cellular immunotherapy

DCs are currently known to be the most powerful antigen-presenting cells in vivo. After expansion and culture in vitro and sensitization of tumor antigens, they can be returned to the patient to promote the proliferation and differentiation of the patient’s T cells into cytotoxic T cells. At the same time, B lymphocytes are activated, and the antibody immune system is fully activated to produce efficient and specific anti-tumor effects.

3. Natural killer (NK) cells—"armored soldier" of cellular immunotherapy

NK cells are important immune cells in the body, which are not only related to anti-tumor, anti-viral infection and immune regulation, but also are involved in the occurrence of hypersensitivity and autoimmune diseases in some cases. The application of NK cells in tumor treatment has already undergone a large number of clinical and preclinical studies, which is another promising direction for tumor cell therapy.

4. CTL/TCR-T/CAR-T cells

precision-guided munition " that kills tumor cells

CTL cells, namely cytotoxic T lymphocytes, have always been a hot spot for immunotherapy of solid tumors (especially malignant melanoma, gastric cancer, colorectal cancer, liver cancer, prostate cancer, lung cancer, cervical cancer, etc.). The tumor-killing mechanism is clear, and it can directly kill tumor cells by releasing two cytotoxins. Recently, T cells modified by cell engineering have gradually become a new focus of global scientists. T cells modified with T cell receptor genes (TCR-T) and T cells modified with chimeric antigen receptors (CAR-T) are both T cells modified by transgenic technology, and both show stronger anti-tumor activity than previous CTL cells with a good clinical application prospect.

Biotherapy has small side effects. In addition, by stimulating the body's own immune system, it has a systemic anti-tumor effect with a wider scope of action. It is especially suitable for malignant tumors with multiple lesions or extensive metastasis. Moreover, the targets of biotherapy are clear without side effects on normal cells.

Biological treatment after tumor surgery can significantly enhance the immune system function of patients, helping remove residual cancer cells and micrometastasis in the body after surgery, and reducing the chance of local recurrence and distant metastasis. Carrying out biotherapy during the interval of radiotherapy and chemotherapy can also help patients to enhance the tolerance of the side effects of radiotherapy and chemotherapy, as well as the ability to resist tumors, thus improving the comprehensive treatment effect of malignant tumors.