Carcinogens

Cancer requires two events: initiation and then promotion. A chemical that causes either initiation or promotion can act as a carcinogen, a molecule that can cause cancer. Some herbal molecules can prevent cancer by thwarting either mechanism, but there are plant molecules that cause cancer, too.

Initiation damages a cell's genes, resulting in a dysfunctional protein. Initiation involves changes in the genes of a normal cell, and these sorts of accidents happen all the time, every day, and are almost always repaired by enzymes, which can detect these changes. Most genetic changes, called mutations, do not produce cancer. Mutations either have no effect or end up killing the cell, which is really no big deal and is usually for the best. Cells die all the time, and it is often good that they do. It is when cells do not die and instead reproduce uncontrollably that they form a clump of mutant cancer cells, called a tumor.

A gene carries coded instructions that passively tell the cell how to make a specific protein, designating which unique sequence of smaller building-block molecules, called amino acids, should be strung together, to form the protein. It's sort of like a blueprint in a book in a library, and the library is DNA, a molecule with massive collections of different genes in it. A gene's instructions may or may not get "read" by the cell, but when it does, copies of the instructions-sort of like a photocopy of the blueprint in molecular forms-leave the DNA to make themselves available to protein-making machinery in the cell. A particular protein is made with the help of the genes' instructions, which remain in place in the DNA to be read again and again.

The instructions for making a protein simply outline the proper sequence of amino acid building blocks that ought to be strung together into a chain, which becomes the protein. It's like instructions for making a necklace with twenty possible different beads, because there are about twenty different amino acids that can be linked into chains to make proteins. Because different types of amino acids tend to interact with each other in different ways, using electrostatic forces, the types of amino acids used and their sequence determine how this chain folds up to become an active, three-dimensional protein.

Most gene mutations are harmless. The trouble tends to arise if the gene codes for a protein involved in cell division or growth. If a gene carrying the blueprint for a protein concerned with cell growth or division is mutated, an unsuitable amino acid might be substituted for the right one, or some may be omitted, and then problems can arise with the protein's structure and function. Cancer can occur when the error resides in a protein concerned with cell growth or division. There are many such proteins. Some turn on cell reproduction, and some turn it off.

A mutated gene that does cause cancer is called an oncogene. Actually there is good evidence that it typically takes as many as five or six separate DNA mutations in one cell to create a cancer cell. While cancer can occur at any age, many forms of cancer are age-related, since it takes time for these errors to accumulate. Some people have a genetic predisposition to cancer, because they have inherited one oncogene already.

Natural and synthetic molecules alike can cause initiation events. Carcinogens that alter genes are sometimes called mutagens or genotoxins. Some carcinogens are synthetic, but there are also plenty from nature. Some work by sticking irreversibly to DNA, the molecule that contains genes, causing errors to be made when the gene is copied, or "read," to make a protein. Also, high-energy light particles, photons, can act like minuscule bullets, barreling through a cell and damaging a strand of DNA. Ultraviolet light from the sun or any other source for that matter, including tanning booths, despite what their proprietors tell you - causes skin cancer, because it barrages your cells with high-energy photons.

In some cancers, a protein that normally turns on cell division might be faulty if its gene blueprint gets mutated, remaining stuck in the "on" position, so to speak. In other cases, a mutation might code for an incompetent growth-halting protein, which is unable to turn cell division off. Not only are there different types of cancer, based on what type of cell is growing awry, such as breast, colon, or lung, there are also different mechanisms that can cause one type of cell to divide continuously, so there are several different types of breast cancer, for example. This is why claims to "cure cancer"- that is, all cancers-reek of shadiness. That a potential cure for some forms of cancer exists is far more persuasive.

Initiation does not mean you will get cancer. It's just step one. Either unrestrained growth-promoting proteins or impotent growth-stopping proteins can lead to cancer, but they also might not. Initiation alone does not create cancer. Your body's DNA-repairing enzymes, like shrewd car buyers, recognize genes that are lemons and repair them. Sometimes they initiate processes that cause the cell to destruct in the neat, helpful manner termed apoptosis. It is rare for a mutation to go unrepaired. Your immune cells not only incapacitate foreign enemy cells but these domestic traitors as well, and this happens every day.

Doctors do not like to alarm people unnecessarily, so they do not tell you that you probably have all sorts of mutant cells. It is most likely, though, that these cells will never develop into actual "cancer." If a cancer cell can escape attack from our immune systems, it still requires promotion to become a tumor.

Step two is promotion. Some herbs and synthetic molecules stimulate this, too. After initiation takes place, the mutant gene may sit unused and unrepaired in the cancer cell for years, even until an event stimulates the cell to divide. The progeny cells inherit its oncogenes and continue their own inappropriate divisions. This can be stimulated by outside factors, too. This is promotion. Some carcinogens cause initiation and mutate your DNA. Others cause promotion, stimulating the mutated cells to divide. Sex hormones like estrogen stimulate cell division; so taking estrogen increases the risk of breast cancer. Some herb molecules, too, stimulate cell division and can act as promoters.

Step three, metastasis, mayor may not occur. But again, this can be provoked by either herbs or by synthetic molecules. There is a possible third stage in cancer, metastasis, where a cancer cell breaks free from the primary tumor and travels to another site, where it divides to create another colony of cancer cells, another tumor. Benign cancer cells do not do this; their tumors can be removed cleanly. Those cancer cells brandishing enzymes that are needed to chew through adjacent tissue can enter blood vessels and spread, and are malignant. Metastases make cancer especially difficult to treat.

Don't panic. There are many herbs, synthetic molecules, and other treatments that can stop all these events, too. Poisons that kill rapidly growing cells are the classic chemotherapy drugs used to target cancer cells. They often work by fouling up some mechanism of cell division, like the duplication of DNA prior to division. Some of these poisons have been isolated from plants. Vincristine and vinblastine, from the periwinkle plant, bind to a cell protein called tubulin, preventing the tubulin from assembling intro structures required to organize chromosomes prior to cell division. In expert hands, these plant derived poisons are carefully used to treat some leukemias, Hodgkin's and non Hodgkin's lymphoma. They should never be used without expertise, because after all, they are poisons.

Radiation also kills rapidly growing cells, penetrating cells like sub-microscopic buckshot that attacks DNA with high-energy light particles. Unfortunately, chemotherapy and radiation both kill innocent, rapidly growing cells, like gut, hair, skin, and blood cells, creating nasty side effects like nausea, hair loss, and weakened immunity. If the side effects can be endured, these therapies can work to bring about remission of the cancer. New chemotherapeutics, like those that prevent tumors from recruiting their own blood supply, or ones that program our immune systems to attack the cancer, are emerging as exciting alternatives to traditional chemotherapy and radiation.

Many herb molecules prevent cancer by neutralizing genotoxins, and initiation is apprehended. Others can slow cell growth, preventing existing tumors from getting any bigger. Some herbs provoke the immune system into killing cancer cells. Toxins in small amounts in some plants stimulate the production of DNA repair and other anti-cancer enzymes. Anti-inflammatory herbs may help, because inflammation is a process known to weaken tissues and facilitate the spread of metastases. Because cancer is a complicated, multi-step process, some herb molecules that affect these steps can cause cancer, but other herb molecules have the potential to prevent and cure cancer.

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