Cancer: Pathophysiology, Treatment Options, and Current Research

As the incidence of cancer continues to rise and with the tremendous trauma that affected individuals must undergo during current treatment, scientists are tinkering with various theories on how to combat this dreaded disease. Cancer is not an infectious bacteria or virus; it is simply a good cell gone bad. A cancer or tumor is a mass of cells that maintain uninhibited growth and eventually kill the host organism by either leading to the destruction of vital organs or by consuming vital proteins otherwise designated for healthy tissue.

Pathophysiology

A healthy individual has trillions of cells that divide at an orderly rate with a controlled pace. However, as a result of various carcinogens and exposure to ultraviolet light which cause DNA mutations, three things happen which turn the once normal cell into a cancer cell: (1) the conversion of protooncogenes to oncogenes, (2) the inhibition of tumor suppressor genes, and (3) the inhibition of DNA repair genes. In the first step protooncogenes, which encode proteins for cell growth and which are normally tightly regulated, become oncogenes whereby they never stop producing growth related proteins. In the second step, genes that would normally suppress these oncogenes get turned off. In the third step the genes which encode the proteins which fix DNA mutations get turned off stunting the cells ability to regain control. Basically if any of these three things do not occur then the cell would either remain normal or the cancer cell would form but not survive. The immune system also contributes to destroying cancer cells by recognizing abnormalities on the cancer cells membrane. These various defense mechanisms explain why the rate of cancer in human beings is relatively low compared to world population.

In the early stages after a cell becomes cancerous it multiplies at feverish rates in one place; at this point it is considered benign. However, if left untreated the cancer becomes malignant and begins to spread through the circulatory system embedding itself wherever it sees fit.

Current Treatments

The cancer treatments available today include chemotherapy, radiation, and surgery. Surgery is usually the best option especially if the cancer is caught early enough. The idea is to remove the growing mass of cells before they have a chance to become malignant and spread.

Once the cancer becomes malignant the only hope is to use chemotherapy, which basically destroys every dividing cell in the body with the hope that it will kill more rapidly dividing cancer cells then healthy dividing cells. The way some chemotherapy agents work is as follows: In order for cells to divide they must replicate their double stranded DNA and give a copy to each of the daughter cells. During DNA replication proteins called DNA polymerase take individual nucleotides and incorporate them into a growing strand of new DNA. In a "lego-like fashion," each nucleotide is connected to the one before it creating a new strand of DNA. Cancer patients receive an injection of modified nucleotides which get incorporated into these growing strands of DNA. However, these nucleotides are chemically modified so that no new nucleotides can be added after them. Thus production of the new DNA strand ceases and the new daughter cells are incapable of survival. The downside to this is that the drugs fail to distinguish between cancer cells and other dividing cells. Thus the rapidly dividing cells that line your digestive tract and hair follicles die and patients suffer from vomiting and hair loss as well as other unpleasant side effects.

Radiation treatment is also used to destroy cancer masses. In this procedure the area where the cancer is growing is carefully mapped out by computer software and then a beam of radiation is directed against that area from different angles. This procedure maximizes damage to the cancer while minimally effecting surrounding tissue. Radiation causes mutations in DNA which prevent the cancer cells from dividing into healthy daughter cells.

Current Research

Novel research has opened up new light on how to possibly cure this dreaded disease. In order for a cancer to grow it must create blood vessels which can continue to feed its heavy demand for oxygen and other basic nutrients. The process of blood vessel growth is called angiogenesis and is a process which rarely occurs in healthy adults. Scientists hypothesized that by giving a cancer patient angiogenesis inhibitors, the cancer would be forced to stop growing and would eventually self destruct as time goes on.  To test this theory, scientists induced cancer in lab rats and then treated them with various angiogenesis inhibitors. The results were astonishing. Most of the rats had a reduction in the size of the tumor and some were totally cured. Scientists and medical professionals rushed to conduct clinical trials. Humans with very severe forms of cancer were given these angiogenesis inhibitors. However, few patients responded to the treatment and the study quickly lost interest in the eyes of those funding and conducting it. The results of these experiments remains mixed. According to some the patients used were already "hopeless" and therefore the medicine never really got a chance to work. Other scientists however disagree and say that the human form of cancer is more complex then in rats and that the cancer is able to produce its own blood vessels which can evade the medication.

Another area of research is to engineer a protein called an antibody and design it to bind to all cells which display cancer proteins. Attached to these antibodies would be small packages of cytotoxic chemicals which would kill the cancer cells. The problem facing scientists with this approach is that since cancer is simply a normal cell gone bad there are no known proteins that are expressed which antibodies could be designed against that wouldn't affect other normal cells. In other words there is no known way to tell an antibody to "go and attach to only cancer cells and leave all other cells alone." Another problem is that to create these antibodies scientists must grow them in rabbits. When these antibodies are injected into humans, the body's own immune system attacks and destroys them before they can reach the cancer cells.

However all scientists and medical professionals agree that taking medications and vitamin supplements to help boost the body's immune system against the cancer is vital for complete recovery and helps to protect against future attacks.