What causes cancer?
Most cancers are not purely hereditary or only caused by acquired mutations. Many types of cancers are caused by a combination of genetic inheritance, or heredity, and the environment. For example, you have an increased risk for skin cancer if you have
family history of skin cancer, but if you never go in the sun, you will be much less likely to develop skin cancer. The mutations acquired from environmental exposure are called somatic mutations. They cannot be passed on to the effected person’s
descendants. Somatic mutations differ from germline mutations, which are inherited. You may inherit germline mutations from your parents which increase your risk for skin cancer. When you go in the sun, you can acquire somatic mutations that increase
your mutation load, the combination of all somatic and germline mutations. Mutation load can be determined by sequencing, such as exome sequencing,
and can be a powerful predictor of a person’s risk for developing cancer or, if they have cancer, their response to treatment.
There are two main areas of focus for cancer research: prevention and treatment. Understanding how cancer develops can help researchers find methods for both areas. Cancer research is furthered by cancer genomics testing. Genomics testing can reveal biomarkers,
or genes that indicate risk, to guide clinicians when personalizing immunotherapy. Immunotherapy can boost the immune system of the patient or suppress growth of the tumor, increasing the patient survival rate. Cancer treatment research has two approaches:
tumor profiling and mutation load. A patient’s genotype can give clinicians insight into how they will respond to
a specific cancer therapy. If the person’s cancer is at an advanced stage, their tumor may have developed some of its own somatic mutations. In this case, the clinician can use the tumor's genomic data to choose the most effective therapy with
the least side effects to the patient. Tumor profiling is performed using whole genome sequencing,
a genetic sequencing approach to find mutations in the tumor. Tumor-normal profiling compares the genetic profile of tumors to the genetic profile of healthy tissue and can achieve better sensitivity with exome sequencing.