Cancer refers to a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. If not managed, it can result in death. These abnormal cells can invade nearby tissues and, through the blood and lymph systems, metastasize to distant parts of the body.
Normal cells grow, divide, and die in a regulated manner. In contrast,
cancer cells bypass these controls, leading to excessive cell proliferation and survival. They ignore signals that normally tell cells to stop dividing, specialize, or undergo
apoptosis (programmed cell death).
Cancer can be caused by a variety of factors, including genetic mutations, environmental exposures, and lifestyle choices.
Carcinogens such as tobacco smoke, radiation, and certain chemicals can increase the risk. Additionally, infections with certain viruses, such as human papillomavirus (HPV), can contribute to cancer development.
Genetic mutations can affect the function of
oncogenes and
tumor suppressor genes. Oncogenes are mutated forms of genes that normally promote cell growth, while tumor suppressor genes are those that typically control cell division and repair DNA errors. Mutations in these genes can lead to cancer.
Cancer spreads through a process called
metastasis. This involves cancer cells breaking away from the original tumor, traveling through the body via the bloodstream or lymphatic system, and forming new tumors in other organs. The ability to metastasize makes cancer particularly dangerous and difficult to treat.
The
tumor microenvironment consists of the surrounding blood vessels, immune cells, fibroblasts, signaling molecules, and the extracellular matrix. This environment plays a crucial role in cancer progression by influencing tumor growth, immune evasion, and resistance to therapies.
How Do Cancer Therapies Work?
Cancer therapies aim to eliminate cancer cells or halt their growth. Common treatments include
chemotherapy, which uses drugs to kill rapidly dividing cells, and
radiation therapy, which uses high-energy particles to damage the DNA of cancer cells. Targeted therapies focus on specific molecules involved in cancer growth, while
immunotherapy leverages the body's immune system to fight cancer.
What is Cancer Immunoediting?
Cancer immunoediting describes the interaction between the immune system and cancer cells. It involves three phases: elimination, equilibrium, and escape. In the elimination phase, the immune system detects and destroys cancer cells. In the equilibrium phase, some cancer cells survive but are controlled. In the escape phase, cancer cells evade immune detection and grow unchecked.
The
hallmarks of cancer are a set of characteristics that differentiate cancer cells from normal cells. These include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis.
Cancer is diagnosed through a combination of medical history, physical examinations, imaging tests, laboratory tests, and biopsies. Imaging tests such as CT scans and MRIs help visualize tumors, while biopsies provide tissue samples for histological examination to confirm the presence of cancer cells.
The future of cancer research is promising, with advancements in
precision medicine, early detection, and personalized therapies. Researchers are exploring the use of
genomics and
biomarkers to tailor treatments to individual patients and improve outcomes. Additionally, new strategies such as
cancer vaccines and
gene therapy hold potential for transforming cancer care.
