Tumor initiation is the initial process of cell changes that result in the formation of a tumor and typically refers to cancer. These changes are related to exposure to carcinogenic substances that alter the DNA and other structure of certain cells, and once the changes occur, they are not reversible. The process of tumor initiation leaves the cells vulnerable to future exposures to carcinogens, and these subsequent exposures will typically trigger the growth of cancer cells.
Many substances are known to act as mutagens, which are substances that interact with the cellular deoxyribonucleic acid (DNA) and can cause changes to the cellular structure. About 70% of these act as tumor initiators and will start the changes to the cells that can ultimately lead to the development of cancer. The other 30% do not trigger tumor initiation, but drug-metabolizing enzymes in the body can turn a non-carcinogenic mutagenic compound into one that can ultimately cause cancer, resulting in the same effect.
Those mutagens that cause tumor initiation are considered to be carcinogenic in that they contribute significantly to the growth of cancer. In many cases, however, the initiators must be followed by a tumor promoter, which is a substance that turns already damaged cells into tumors. Promoters may be a completely different type of mutagen, or they may be the same one that caused tumor initiation. If a single substance is both an initiator and a promoter, it is referred to as a complete carcinogen, since it can cause cancer without the presence of any other substances.
Cancer during the initiation stage is rarely identified, since at this point it will not have caused any tumors or systemic problems. Once tumors begin to grow it may be found, but the point at which it is discovered will vary. It normally depends on the size and location of the tumors as well as any effects the cancer has caused in the body.
People who are concerned about exposure to mutagens and subsequent tumor initiation can still take certain steps to protect themselves. First of all, minimizing exposure to known carcinogens can prevent tumor initiation and progression in many cases. The regular use of protective gear such as breathing masks, gloves, and clothing by people who work around such substances can help.
According to a report from the British Colombia Cancer Research Centre, eating a low carbohydrate diet can also help to reduce or prevent tumor initiation. According to results released in July of 2011, mice that were exposed to carcinogens but ate a low carbohydrate diet had significantly less tumor growth than those in a control group. It is important to note that this diet was also relatively low in fat, as research has shown that fat may promote tumor growth.
