Every year, an enormous number of people worldwide fall under the trap of cancer and more than half lose their battle to this chronic disease. Among the multimodalities of cancer management, including surgery, hormonal therapy, radiotherapy, and chemotherapy, immunotherapy has revolutionized the treatment of cancer. Immunotherapy, also known as Immune-oncology, is a rapidly developing and exciting field of cancer treatment with the perspective of impacting the management of a wide array of malignancies that have recently witnessed a steep rise.
The major goal of cancer immunotherapy is to alleviate tumor-associated suppression of anticancer immune responses. Cancer immunotherapy, which is occasionally referred to as immune-oncology, induces the patient’s own immune system and attempts to exploit the exquisite power and specificity of the immune system for cancer patient treatment. Immunotherapy against cancers encompasses a diverse spectrum of approaches, ranging from stimulating effector mechanisms to counteracting inhibitory and suppressive mechanisms. Owing to the swift knowledge amassed by the scientific community about the immune system, small molecules, peptides, recombinant antibodies, vaccines, and cellular therapeutic modalities are being applied to manipulate the immune response to treat cancer.
Immunotherapy helps the immune system recognize, attack, and destroy cancerous cells. Let us look at 5 different types of immunotherapy in brief:
1. Adoptive Cell Therapy
Adoptive cell therapies use immune cells to fight cancer. There are two main approaches:
a) Immune cells are isolated, expanded, and reintroduced into the cancer patient
b) Immune cells are genetically modified to “boost” their cancer-fighting ability, and then reintroduced into the cancer patient.
2. Cancer Vaccines
Unlike bacteria and viruses, which are easily recognized by our immune system as “foreign”, cancer cells more closely resemble our “normal” cells – meaning it is much more challenging to generate vaccines against them. As a result, more sophisticated approaches are essential to developing effective cancer vaccines.
Immunomodulators regulate or “modulate” the activity of the immune system. Immunomodulating agents can be used to adjust the level of activity by stimulating or suppressing the immune system to help fight cancer.
4. Targeted Antibodies
An antibody is a protective protein produced by B cells in response to a specific antigen. Scientists can harness the power of antibodies to supplement a patient’s own immune system by synthesizing “customized” antibodies. These antibodies specifically target antigens that are typically found in greater numbers on the surface of cancer cells compared to “normal” cells.
5. Oncolytic Virus Therapy
Viruses are infectious agents that are capable of infecting living cells, hijacking their genetic machinery, which allows the viruses to replicate inside of them. Modified versions of viruses can be created to target and attack cancer cells. These are termed “oncolytic viruses” as they are designed to target cancer specifically. The viruses can be engineered to decrease their ability to infect “normal” cells and they can also be used as delivery vehicles, transporting therapeutic payloads to cancer cells.
Although immunotherapy is not used as widely as chemotherapy, surgery, or radiation, advances in this area have made it a great option for treatment in many types of cancers. Immunotherapy can “train” the immune system to remember cancer cells and this “immune-memory” may result in long-lasting disease remissions which are maintained even after the treatment is completed.