Thursday, September 7, 2017
Friday, October 12, 2012
Cancer formation begins when DNA in a cell or population of cells is harmed after exposure to carcinogens. These cancer-producing toxins can come from the person’s environment or be a product of regular bodily processes. For example, long-term exposure to viral or bacterial infection may cause chronic inflammation that hurts cells and DNA. Ultraviolet and gamma radiation can also injure DNA. Or a person’s normal oxidative metabolism can generate reactive oxygen species (ROS) carcinogens, which in turn can attack DNA.
Many exogenous (from outside the body) carcinogens need to be activated by metabolic enzymes, but detoxification enzymes such as the glutathione S-transferases also exist to deactivate carcinogens or their intermediate metabolites. People who have inherited genetic variations known as polymorphisms in these types of enzymes may have altered rates of enzyme activation or detoxification, thus increasing or decreasing the carcinogenic potential of environmental exposures. In other words, they will have advantages or disadvantages when it comes to how their bodies deal with carcinogens. Carcinogens can also induce cancer by affecting epigenetic changes, such as DNA methylation, which alter a gene’s activity without changing the underlying DNA sequence. Once the cancer process has begun, either the cell’s defense mechanism detects the abnormality and targets the cell for destruction or the accumulation of further genetic defects helps the flawed cell escape these defenses. The defects may also give these mutated cells a growth advantage, so that they multiply and spread from the site of origin to other sites in the body. In essence, cancer develops from the build-up of DNA damage and changes over several years and from many causes. This explains why aging is a major risk factor associated with most cancers. Less than 0.1 percent of the total number of cancer cases occurs in people younger than 15, whereas nearly 80 percent of cancer cases are found in people age 60 or older.
Several factors inside the body and in the environment play a role in the development of cancer. Environmental exposure to a variety of natural and manufactured substances makes up at least two-thirds of all cancer cases. These include lifestyle choices such as smoking tobacco, overindulging in alcohol, poor diet, lack of exercise, excessive sunlight exposure, risky sexual behavior, and increased exposure to some viruses. Other causes may include exposure to certain drugs, hormones, radiation, viruses, bacteria, and environmental chemicals present in the air, water, or workplace. Most chemicals are not carcinogenic, but a wide variety of chemicals can promote the disease. And so cancer is a multifaceted genetic disease that often requires multiple genetic lesions to breach the body’s safeguards. Even people who have inherited flaws in critical protective genes usually do not develop cancer for many years. Yet in many if not most humans the massive accumulation of mutations during a lifetime ensures that some form of malignant disease will eventually develop.
Thursday, May 10, 2012
To screen or not to screen…………….
There is scientific proof to show that a commitment to a healthy lifestyle may prevent cancer. A few key examples include eating nutritious food, exercising regularly, and avoiding tobacco smoke. However, some individuals may be prone to developing cancer because of an inherited genetic mutations or exposures to toxic environmental factors such as radiation or other unidentified risk factors, particularly if the exposure happens in childhood or infancy. So even if a person takes precautions and makes lifestyle changes to avoid cancer, he or she may already be predisposed to develop the disease later in life. Therefore it is important to undergo screening such that any premalignant disease can be detected early when there is good chance for a cure.
Yet screening is among medicine’s most controversial topics. A major challenge is that it can be difficult to determine if a particular cancer will advance rapidly, progress more slowly, or possibly, not develop at all. In many cases, people who have an indolent cancer or a benign disease will die from other causes before they die from cancer, so detection and treatment are unnecessary and offer no benefit whatsoever. Worse, the treatment could itself cause unnecessary stress, harm, even disfigurement. Slow cancers, by their dawdling nature, frequently have a longer pre-symptomatic period, increasing the likelihood of discovery and improving the chances of treatment. These cancers may be well worth catching. With particularly aggressive cancers, the disease can move so quickly that early detection and treatment cannot help. Another factor influencing outcomes is that the attitude people have about cancer may help decide whether they live or die (and how quickly) from the disease. The goal, then and also a major scientific challenge, in cancer screening is to determine who would benefit the most from early detection. The good news is that scientists are getting closer to identifying specific gene expression signatures that may help predict if cancers will be aggressive or not.
The screening tests now available can indicate susceptibility to various cancers including, breast, colon, lung, prostate, cervical, endometrial, ovarian, pancreatic, and melanoma cancers and can often be performed in clinics or laboratories. While there remains questions about the risk-to-benefit ratio cancer screening, once resolved, the benefits of cancer screening should be clear—as well as the possibility of eradicating cancer.
Read more in Cancer Causes and Controversies- Understanding risk reduction and prevention....
Wednesday, March 21, 2012
Monday, March 12, 2012
Stomach cancer, is the second-most-deadly cancer worldwide. The incidence of this cancer, however, varies with location. The highest-risk countries are in Asia, especially Japan, Korea, and China. As stomach cancer usually shows few early signs, most people are not diagnosed with this disease until it has advanced. Symptoms typically include loss of appetite, indigestion, stomach pain or discomfort, a bloated feeling after meals, nausea, and heartburn.
The main risk factors linked to stomach cancer risk include tobacco use, a poor diet, excessive alcohol consumption, and chronic infection (chronic gastritis or stomach inflammation) from Helicobacter pylori (H. pylori) bacteria. There is also evidence that some people may have a genetic vulnerability to this disease; studies of twins show higher than expected concordance rates of stomach cancer among identical twins.
Preventative measure- Healthy diet rich in fruits and vegetables, avoidance of smoking and excessive alcohol consumption, avoidance of contact with H. pylori (e.g., good sanitation) and knowlege of family history.
"Excerpts from Cancer Causes and Controversies- Understanding risk reduction and prevention"
In memory of Tracie.
You were always a kind and a selfless person, always willing to help. Its was a pleasure to know and work with you. I know how brave you were during your illness and even though your death saddens us all greatly, I know that you are in a beautiful place, where there is no more pain and suffering. I hear it is a place where the sun always shines on an unclouded sky, a beautiful city, a heavenly city of love. Rest in peace!!!!!!!!!!!!!
Friday, March 9, 2012
Ovarian cancer strikes fewer than half as many women as endometrial cancer, yet ovarian cancer has double the mortality rate. The symptoms for this cancer tend to be vague at first. As the disease progresses, women may experience discomfort or pressure in their pelvic area, back, abdomen or legs. They may feel fatigued, bloated, nauseated, constipated, and have diarrhea or indigestion. Some women experience breathlessness, vaginal bleeding·even after menopause·and feel they have to urinate frequently.
Endometrial cancer (also known as uterine cancer) develops in the tissue lining the uterus. This disease is a few steps ahead of ovarian cancer in terms of how frequently it is diagnosed, but it tends to be much less deadly. Women with early-stage endometrial cancer may experience unexplained vaginal spotting or bleeding between menstrual periods or after menopause (when they should not experience any bleeding). They may have pain or difficulty during urination, discomfort during sex, or pain in the pelvic region. Individuals with any of these symptoms should see a doctor for propergynecological examinations.
Risk factors associated with ovarian and endometrial cancers includes:
Age over 55 years. Diet high in total fat content (in particular animal fat). Because fat stimulates the body's production of estrogen hormone which in turn increases ovulation thereby increasing cancer risk. Genetic predisposition in familes with mutation in the DNA repair genes known as BRCA1 and BRCA2 genes. Ionizing radiation, obesity and diabetes are associated with increase risk to ovarian and endometiral cancer.
Healthy diet rich in fruits and vegetables and moderate level of excercise (avoidance of sedentary lifestyle) are all associated with reduced risk of this type of cancer.
For detailed information read "Cancer Causes and Controversies- Understanding risk reduction and prevention"