Answer: Is a result of genetics and environmental factors.
Step-by-step explanation:
Cancer is the common name for a group of diseases in which there is a division of the body's cells, whose growth exceeds that of normal tissues and which persists in the same excessive manner. It can begin in a localized manner and spread to other surrounding tissues and its malignancy is very variable, according to the aggressiveness of its cells and other biological characteristics of each type of tumor. In general, the behavior of cancer cells is characterized by lacking the reproductive control required by their original function, acquiring the capacity to invade tissues (metastasis), spreading through the organism via the lymphatic or circulatory system, and causing the growth of new tumors in other parts of the body.
A gene is a hereditary unit composed of DNA that carries the instructions for producing proteins, which do much of the work in our cells. Certain genetic alterations can cause cells to evade growth controls and become cancerous cells. These changes can be inherited from our parents if the changes are present in the germ cells (eggs and sperm) and they are called germline changes. In addition, cancer-causing genetic changes can also be acquired during a person's lifetime (somatic or acquired changes), as a result of DNA errors that occur when cells divide either spontaneously or by exposure to carcinogenic substances that damage DNA (environmental factors), such as certain chemicals in tobacco smoke, or radiation, such as ultraviolet rays from the sun. These substances damage DNA, acting as mutagens.
Sometimes, the changes are not in the DNA sequence. For example, the epigenetic modifications are the presence of chemical marks in DNA which can determine if the gene is expressed. This means, whether and how much messenger RNA is produced, because the messenger RNA is translated into proteins.
So, cancer cells have genetic changes compared to normal cells. These changes are due to mutations that can be inherited, acquired spontaneously during life, or acquired due to environmental factors such as sun exposure, smoking, and other factors. In addition, the fact that a person has the cancer-related mutation does not necessarily mean that he or she will develop the disease during his or her lifetime. In some cases, even if they have this genetic vulnerability, they remain healthy, because cancer is a multifactorial disease that depends on many factors, such as the immune system, nutrition and certainly many others currently unknown to medicine.