The Gale Encyclopedia of Cancer 4th Edition PDF
131.5 MB PDF
diseases are totally reversible and can be effectively treated. Moreover, some diseases with proper treatment have been virtually annihilated, such as polio, rheumatic fever, smallpox, and, to some extent, tuberculosis. Other diseases seem to target one organ, such as the heart, and there has been great progress in either fixing defects, adding blood flow, or giving medications to strengthen the diseased pump. Cancer, however, continues to frustrate even the cleverest of doctors or the most fastidious of health-conscious individuals. Why?
By its very nature, cancer is a survivor. It has only one purpose: to proliferate. After all, that is the definition of cancer: unregulated growth of cells that fail to heed the message to stop growing. Normal cells go through a cycle of division, aging, and then selection for death. Cancer cells are able to circumvent this normal cycle and escape recognition to be eliminated.
There are many mechanisms that can contribute to this unregulated cell growth. One of these mechanisms is inheritance. Some individuals can be programmed for cancer due to inherited disorders in their genetic makeup. In its simplest terms, a person can inherit a faulty gene or a missing gene whose role is to eliminate damaged cells or to prevent imperfect cells from growing. Without this natural braking system, the damaged cells can divide and lead to more damaged cells with the same abnormal genetic makeup as the parent cells. Given enough time, and our inability to detect them, these groups of cells can grow to a size that will cause discomfort or other symptoms.
Inherited genetics are obviously not the only source of abnormalities in cells. Humans do not live in a sterile world devoid of environmental attacks or pathogens. Humans must work, and working environments can be dangerous. Danger can come in the form of radiation, chemicals, or fibers to which we may be chronically exposed with or without our knowledge. Moreover, humans must eat, and if our food is contaminated with these environmental hazards, or if we prepare our food in a way that may change the chemical nature of the food to hazardous molecules, then chronic exposure to these toxins could damage cells. Finally, humans are social. They have found certain habits that are pleasing because they are relaxing or help release inhibitions. Such habits, including smoking and alcohol consumption, can have a myriad of influences on the genetic makeup of cells.
Why the emphasis on genes in the new century? Because they are potentially the reason as well as the answer for cancer. Genes regulate our micro- and macrosopic events by eventually coding for proteins that control our structure and function. If environmental events cause errors in those genes that control growth, then imperfect cells can start to take root. For the majority of cases, a whole cascade of genetic events must occur before a cell is able to outlive its normal predecessors. This cascade of events could take years to occur, in a silent, undetected manner until the telltale signs and symptoms of advanced cancer are seen, including pain, lack of appetite, cough, loss of blood, or the detection of a lump. How did these cells get to this state where they are now dictating the everyday physical, psychological, and economic events for the person afflicted?
At this time, the sequence of genetic catastrophes is much too complex to comprehend or summarize, because it is only in the past decade that we have even been able to map what genes we have and where they are located in our chromosomes. We have learned, however, that cancer cells are equipped with a series of self-protection mechanisms. Some of the altered genes are actually able to express themselves more than in the normal situation. These genes could then code for more growth factors for the transforming cell, or they could make proteins that could keep our own immune system from eliminating these interlopers. Finally, these cells are chameleons: if we treat them with drugs to try to kill them, they can “change their colors” by mutation, and then be resistant to the drugs that may have harmed them before.
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