cancer is a collection of related diseases that can occur almost anywhere in the body and is characterized by abnormal cell process involving uncontrolled cell growth and proliferation that alters normal cell behaviour. there are over 100 types of cancers, and in all types, cancer is caused when certain changes occur to genes that control the way cells function, especially how they grow and divide. when cells start to multiply and divide outside of the normal cell process and they start to invade surrounding tissue. human cells grow and divide to form new cells as the body needs them, when cells grow old or become damaged, new cells take their place. when cancer develops this process breaks down and new cells from growths or tumours. all cancers are a result of changes that have occurred in the DNA.
these changes to the DNA may be produced by environmental factors such as
- lifestyle [nutrition, tobacco use, physical activity]
- exposure [ultraviolet light, radon gas, infectious agents]
- medical treatments [radiation]
- workplace and household exposures [mold and other toxins]
cancer can also occur from randomly occurring DNA copying mistakes [a 2017 study suggests that 2/3 of cancers are due to these errors]. genetic changes that have occurred throughout a person’s life [not acquired at birth] are called somatic mutations. cancer can also occur from an inherited mutation [eg.BRCA1] this type of mutation which is inherited is called a germline mutation. it is important to understand that not everyone who inherits a mutation will develop cancer.
regardless of how the cancer occurred, the genetic alterations within the cancer cells will be manifested by the release of biomarkers. and often, the genes continue to mutate, changing the cells in the tumour over time. when a tumour’s molecular structure changes, this may develop into resistance to a certain treatment – essentially the cancer has mutated into a different form.
understanding how genetic changes cause cancer is one way to understand this disease.