Cancer is a collection of related diseases caused by abnormal cell growth in a patient’s body. It occurs when normal checks on cellular division cease to function, resulting in excessive growth of cells in a specific tissue the body cannot control on its own.
Cancer is not one single disease, and it develops from a patient’s own cells. It can occur in virtually any tissue in the body – from bone, to skin, to brain – and a wide variety of mutations can induce it.
The genetic mutations that lead to cancer typically:
- Disable error correction in the genetic code (DNA repair)
- Prevent programmed cell death (apoptosis)
- Circumvent normal life cycles
- Cause cells to reproduce much more quickly than normal
- Compromise a cell’s ability to respond to outside cues
Due to specific mutations that caused it, each individual patient’s cancer is effectively its own disease – making cancer a necessary venue for personalized medicine.
New mutations involved in cancer initiation or progression are constantly being identified. Additionally, once the normal checks on DNA repair stop working, cancer cells can change over time, introducing new treatment options and closing others over the course of the cancer’s lifetime.
The symptoms of cancer are highly variable and depend heavily on which tissue type is affected and the location of the tumors.
The growth of cancerous masses, called tumors, can physically block normal organ function, depending on the tumor’s location. This can lead to symptoms such as shortness of breath, difficulty swallowing, chronic pain and visible lumps. As a cancer grows more severe, it can compromises organ functions and eventually become life-threatening.
Cancers made from glandular tissue, such as thyroid cancer, can lead to over- or under-production of those glands’ secretions, causing widespread effects across the body.
Some tumors discharge fluid or damage nearby tissue with their growth, leading to edema, swelling, and internal bleeding.
The most dangerous cancers form tumors that then begin to break apart and seed smaller tumors elsewhere in the body. This process is called “metastasis” and dramatically increases both the danger a cancer poses to the patient and the difficulty in treating it.
Cancer is a difficult condition to treat and worthy of its own medical and research specialty, oncology.
Because cancers emerge from the tissues of the patient’s own body, they share a fundamental similarity with the host. Many cancers can use this similarity to hide from the host’s immune system.
Common treatments, such as radiation or chemotherapy, often do not distinguish between the two. Effectively, these treatments attack both healthy and cancerous tissue – in hopes of defeating the cancer before the patient suffers too much.
This has created a major research push to find less dangerous ways to treat cancer by making treatments more targeted and personalized.
Cancer research is an ongoing and high-priority research area for scientists.
Scientists work to identify and understand the causes of cancer, including the roles played by diet, environmental toxins and aging. They also work to understand the hundreds of genes involved in cancer and their roles in blocking or encouraging the development of cancers. This is used to develop treatments, often based on new cancer-related genes, to extend the lives of cancer patients.
For more information about cancer research visit our cancer research resource center.