Vaccines against cancer

New advances are being madein cancer treatment. Side by side with the existing therapies including chemotherapy, radiation therapy, targeted therapy (that targets proteins that control growth, division, and spread of cancer cells), andsurgery, new approaches to cancer treatment have been developed. Immunotherapy is one of them. In this method of treatment, the immune system of the body is stimulated or suppressed using substances so the body can fight cancer or other kinds of diseases. In some immunotherapies, certain cells of the immune system are targeted, while in others, the immune system, in general, is affected. Oncolytic virus therapy is one form of immune therapy that involvesnew types of drugs that depend on viruses to choose and attack cancer cells and at the same time stimulate body's immune response against the tumour. The difference between, for example, chemotherapy and immunotherapy is that in chemotherapy, both the cancerous and healthy cells are attacked. But in immunotherapy, the body's immune system is stimulated to destroy the cancer cells without harming the healthy cells. In a recent development, the US Food and Drug Administration (FDA) has given approval to such treatment in whichthe virus in question, herpes,which causesthe common cold sore or fever blisters, has been genetically engineered to fight deadly skin cancer that develops in the melanocytes, cells that produce melanin (melanin is the pigment that gives skin its colour).Scientists first genetically changed the herpes virus so that it lost its capacity to make people sick. Its genewas further modified so it could replicate within cancer cells thereby enhancing its capacity to fight cancer. With the genetically modified herpes virus getting FDA-approval as an oncolytic virus therapy, scientists are now looking into the cancer-fighting potential of other such known viruses such as polio, rabies, and adenovirus.

But these are about our known viruses' potential to fight cancer after necessary tweaking of their genes. But scientists have now found the relics of millions of years old virus hiding in human DNA. These pieces of ancient viruses can wake up to help our immune system to attack malignant tumours in the body.

The discovery has been made by scientists at the Francis Crick Institute in London, UK.This immune-enhancing property of the ancient virus parts has been aninspiration for scientists to develop vaccines that can help treat or even prevent cancer.The researchers have discovered a link between the B-cells(a type of white blood cells which constitute a part of the immune system) that cluster around tumours and ensure a better rate of survival from lung cancer. B-cells produce antibodies that can fight infections. But what were they doing in the lung cancer? Scientists continued research to discover that they were trying to fight a type of virus, the so-called, endogenous retrovirus (a family of viruses lying within our genome). In a cancer cell, the ancientendogenous retrovirusestryto resurrectsegments, if not the ancient viruses in their entirety. The B-cells identify those in tumour cells and consider those as a viral threatand try to destroythose with the help of theentire immune system of the body. That is, these fragments of ancient viruses are in a way protecting humans from cancer. According to a BBC report, the study on how that happens naturally in human body was published in the scientific journal Nature.

However, researchers now want to use the helpful role of the millions of years old viral fragments in thehuman body to develop not only therapeutic, but also preventive vaccines against cancer.

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