Cancer and the Immune System

Cancer and the Immune System in actionCancer is a leading cause of illness and death around the world. While there are many different types of cancers, scientists have identified key hallmarks of cancer, and the properly functioning thymus gland performs a key role in producing cells that identify cells with these hallmark, preventing their growth and preventing neighboring cells from becoming cancerous.

Cancer develops due to mutations in the DNA of once normal cells. These transformed cells often proliferate rapidly and travel to distant tissues causing severe dysfunction. These mutations can be caused by a variety of insults, many of which are inherited, while others are brought on by chemical exposures, radiation, certain viruses, chronic inflammation and diseases. The hallmarks of cancer cells include their ability to stimulate their own growth, resist signals which would lead to cell death and invade local tissue and spread to distant sites (metastasis).

The thymus gland is responsible for preventing cells from gaining these abilities and produces specific immune cells known as T-cells to enable this protection. Cytotoxic T-cells (Killer Cells) are a uniquely powerful immune cell that matures in the thymus. They are directly capable of killing cancerous and pre-cancerous cells which demonstrate hallmarks. After recognizing these hallmarks through a number of mechanisms, cytotoxic T-cells bind to offending cells and deliver signals into the cells which activate a process known as apoptosis leading to programmed cell death. While certain cancer cells are able to evade this mechanism, the vast majorities are not and are killed, and prevented from becoming cancerous.

Cancer immunotherapies are the newest methods of adapting the body’s immune system into therapeutics. Many activate B-cells within the body to produce highly targeted antibodies every second. Others mimic antibodies with specialized kill ability. These antibodies are able to bind to proteins on cancer cells, cutting off vital signaling pathways or marking the cells for attack by other immune cells. Others active CD4+ helper T cells, in order to support other cells, including B cells and CD8+ killer T cells to coordinate joint responses against mutant cells. Additionally, many activate regulatory T cells in order to precisely contain the immune system response.