May 29, 2006

Exercise can reduce the risk of cancer

Insight into the anti-cancer effect of exercise
May 29, 2006 06:23:25 AM PST

The anti-cancer effects of exercise are due to increases in a protein that blocks cell growth and induces cell death, according to Australian researchers.

The protein, called insulin-like binding protein-3 (IGFBP-3), inhibits another protein called insulin-like growth factor-1 (IGF-1), thereby blocking IGF-1's proliferative effect on cell growth, the study hints.

Dr. Andrew M. M. Haydon and colleagues at Manash Medical School in Melbourne identified new cases of colorectal cancer in the Melbourne Collaborative Cohort Study, a prospective study of 41,528 adults recruited between 1990 and 1994.

The investigators looked at baseline body mass index and level of physical activity reported and compared baseline levels of IGF-1or IGFBP-3 with those measurements.

Analyses centered on 443 colon cancer patients followed for more than 5 years.

Among subjects who were physically active, an increase in IGFBP-3 was associated with a 48 percent reduction in colon cancer-specific deaths. No association was apparent for IGF-1.

For the physically inactive, there was no association between IGF-1 or IGFBP-3 and colon cancer survival.

Haydon told Reuters Health that that "physical activity can increase IGFBP-3 levels, which, in turn, reduces the amount of free IGF-1." IGF-1 has been shown to stimulate cell growth, inhibit cell death, and promote angiogenesis -- the formation of new blood vessels, which tumors need to grow.

"We did not look at the amount of physical activity needed to reduce colorectal cancer incidence, as we only looked at those from our cohort who had CRC," Haydon pointed out.

"Other studies that have looked at this have shown a dose-effect, meaning the more exercise the lower the risk, however our study did not try to address this issue. We were examining the effect of physical activity on one's prognosis following a diagnosis of bowel cancer and the possible mechanisms behind this effect."

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drfcshk said...

During the cancer diagnosis doctors look for the site of origin of the tumor and the type of cells. Cancers arise in any organ. The body site, where cancer develops first, is the primary site. The tumor spreads (metastasizes) then. Common cancers include skin, lungs, breasts, prostate, colon and uterine tumors. There are many signs and symptoms of cancer. Doctors may find tumors directly, by X-ray or MRI imaging, or through lab tests.

However, these signs and symptoms of cancer may mimic other diseases. Weight loss and abdominal pain may mean stomach cancer or an ulcer. Weight loss and swollen lymph nodes may mean lymphoma or AIDS or tuberculosis. Blood in urine is a sign of bladder or kidney cancer or a kidney infection. Blood in stool is a sign of many bowel problems, not just cancer. Benign looking skin mole may be deadly melanoma. Doctors often need a biopsy (microscopic check of tissues samples) to diagnose cancer. The cancer type is found by microscopic examination. If the type is different from surrounding tissue, the cancer came from another primary site. Metastases can spread directly or through blood vessels, and lymphatic vessels. Biopsy helps to find the primary site. Treatment also depends on the cancer cell type. Cells could be more or less differentiated and originate from different layers of the same organ. If the cancer cells resemble healthy, mature cells, they are differentiated. Undifferentiated cells look like very immature primitive cells. Checking the differentiation allows doctors to know how aggressive the cancer is. Grade one cancer is less aggressive than grade four usually.

Also doctors classify cancers by stage. Stage depends on the size and spreading of the tumor. Stage determines the mode of treatment - Whether it is surgical, radiation, chemotherapy and so on.