Cancer is a class of diseases in which a group of abnormal growth of cells have become progressively worse as it intrudes upon and destroys adjacent tissues, sometimes spreads to other organs in the body via lymph or blood and results in death of the host.
A. Development of cancer
The development of cancer can be divided into three different stages
Initiation is characteristic by irreversible mutation of DNA of a particular cell which does not undergo DNA repair (by enzymes) or undergoes faulty DNA repair, including gene deletion or insertion, gene slices, etc.
In the promotion stage the mutation cells involve in uncontrolled growth and proliferation of mutated cells as it promotes the expression of its mutation gene and in its replication. In time these cells loose their normal abilities and just reproduce.
In the progression stage, the cancerous cells invade nearby tissues and migrate to other tissues via lymph or blood.
B. Antioxidants and cancer
Antioxidants are molecules capable of inhibiting the oxidation of other molecules to prevent damage by free radicals. Free radicals are unstable molecules due to lost of an electron. By maintaining the stable condition to itself, it causes oxidation to others that leads a chain of oxidation reaction, causing more free radicals being produced during the process, until they are brought to stop, causing alternation of DNA, resulting in possible development of cancer.
As we mentioned in the Antioxidants section above, there are many types of antioxidants
which search for free radicals and destroy them, thus preventing further damage to other cells, resulting in lessening the risk of the development of cancers.
C. Risk factors
a. Environmental exposures can promote the formation of free radicals, including sunshine, radiation, hormones, viruses, bacteria, air pollution, contaminated water and food, and chemical in the workplace, etc.
Bad choices of lifestyle including cigarette smoking, excessive drinking, an unhealthful diet, lack of exercise, or sexual behavior can increase the risk of free radical causes of oxidation.
Although there is no specific guidance but studies show that consuming large quantities of red meat, preservative, and salt and less on vegetables and fruits increase the risk of stomach and colorectal cancers and calorie restriction has been shown to reduce cancer risk for several cancer types in experience in mice.
There are many healthy foods contained antioxidant which can help to reduce the risk of cancers, you can find over hundred of them in the link: healthy food index
All types of tobacco smoking can cause a billion of oxyradicals within a signle puff due to its carcinogens , free radicals and chemical, leading to a dozen types of cancer, including lung, mouth, bladder, colon, and kidney cancers. Chewing tobacco and snuff increase the risk of oral cancer, and second-hand smoke increases the risk of lung cancer.
Although it is only account 5% of diseases but in some cases, cancer is caused by an alternative gene that is being passed along from generation to generation, leading to increasing the risk of cancer, not the cancer itself.
4. Random gene change
Random gene change caused by exposuring to a particular chemical which are accumulated in great amount as it passed along in cell division and replication can increase their risk for cancer.
5. Faulty Gene Repair Activities
Environmental exposures cause an unwanted molecule to bind to a gene, leading to the genes in faulty production of mutation of repair proteins in the gene repair activities that produce more alternation passing through from generation to generation. .
Some chemotherapy drugs used to treat cancer may increase the risk of second cancers later in life due to its suppression of the immune system in fighting against the forming of free radicals.