Monday, October 23, 2017
Thursday, September 7, 2017
Friday, October 12, 2012
CANCER IS A MULTISTAGE PROCESS
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!!!!
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.
My tribute to Tracie- Died of stomach cancer
Dear 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!!!!!!!!!!!!!
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Memento mori!!!!!!!!!!!!!!!!!!!!!! |
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