Comprehensive information site on mesothelioma diagnosis, treatment, coping, asbestos disease and financial assistance.

Mesothelioma: Angiogenesis Therapy

Cancer cells, like other cells in the human body, rely for their growth on a rich supply of blood. They must be surrounded by an effective network of capillaries and larger blood vessels that nourish the cells. The medical term for the process of developing this network is angiogenesis.
In fact, fast-growing cancers are highly efficient at promoting angiogenesis. They produce angiogenesis promoters that create capillaries and a network of blood vessels around the tumor. The tumor is nourished with an increasing supply of oxygen-rich blood, and it grows and spreads (or metastasizes).

Understanding that angiogenesis is fundamental to the process of how tumors grow and metastasize, medical researchers started to investigate how they could slow down, stop, or reduce angiogenesis. If they could do this, they reckoned, they could starve the tumor to death - or at least slow its growth significantly. The National Cancer Institute has created an illustrated teaching tool to better understand how angiogenesis works.

A number of antiangiogenesis drugs, also called angiogenesis inhibitors or angiogenic inhibitors, have been developed. When administered to laboratory animals with tumors, they have caused the tumors to shrink or even disappear. Endostatin, combrestatin, angiostatin, thrombospondin, and vascular endothelial growth inhibitor (VEGI) are among these experimental drugs.

A few of these drugs are now being tested on humans. One of them, combrestatin, destroys the lining of blood vessels around tumors. Another, endostatin, acts by impeding the growth of new blood vessels around the tumors. For endostatin there have recently been some promising developments. Harvard's Dana-Farber Cancer Institute released an updated report on Phase 1 trials of the angiogenic inhibitor and says it exhibits virtually no toxicity even at high doses, while shrinking tumors in two of 28 advanced cancer patients and slowing disease progression in four others for more than six months.

This area of cancer research holds promise for the treatment of mesothelioma tumors, but it is very much in the early and experimental stages.
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Mesothelioma Breakthrough

By Kylie Walker, AAP medical writer
December 17, 2003

NEW hope is on the horizon for the growing number of Australians with the deadly asbestos-caused cancer, mesothelioma.

Caused by the inhalation of asbestos fibres, mesothelioma has been incurable and almost always leads to death.

However, a promising new compound appears to kill the cells of both mesothelioma and another notoriously difficult to treat cancer, melanoma.

Together the lung and skin cancers claim hundreds of Australian lives every year, and federal government health experts predict about 10,000 more mesothelioma cases will be identified in Australia by 2020.

Professor Michael Millward and his team at Perth's Sir Charles Gairdner Hospital hope their research will lead to a new drug that will beat those cancers and others.

They have recently begun human trials of the compound, derived from the herbal medicine known as Devil's Weed.

"Currently, there are two patients and two more are starting shortly," Prof Millward said.

"We will be looking to treat about 18 to 25 patients between now and the second quarter of next year."

Animal and laboratory tests have shown extremely heartening results.

"We're talking about a reduction in tumour size in animals and outright killing of cells in the laboratory," Prof Millward said.

Most existing chemotherapy drugs trigger a self destruct mechanism in cancer cells, but mesothelioma and melanoma cells are largely immune to this kind of therapy.

The new compound works by unlocking a receptor on the cancer cell, invading the cell, then killing it – much like planting an explosive inside the cell.

However, Prof Millward warned cancer patients should not get too excited about the possible new treatment.

"After this phase we will then evaluate all the results and look at if the drug is safe and whether it may be beneficial, and if that's the case we will then go to trials for specific cancers," he said.

"If the next set confirms this is a promising treatment, then it will take several more years of large trials to know if it's going to be a marketable treatment for cancer."

In other cancer news, human trials are expected to start soon for a new drug that was found in animal studies to kill late-stage human prostate cancer cells.

Melbourne-based drug development company Cytopia said its new molecule halted the normal growth cycle of prostate cancer cells, eventually leading to cell death.

The company hoped to start testing the therapy on humans by mid-2004.
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What is Asbestos?

Asbestos is the common name for any variety of silicate materials that are fibrous in structure and are more resistant to acid and fire than other materials. It has two forms, serpentine and amphibole, and is made of impure magnesium silicate. Asbestos is used for thermal insulation, fire proofing, electrical insulation, building materials, brake linings and has been used in numerous industries.

Serpentine and amphibole asbestos both exhibit physical and chemical resistance to high temperatures and applied force. The raw ore of both forms is made up of fibrous strands. The strands then continue to split into smaller and thinner fibers as disturbance continues and increases. Asbestos' ore form will initially divide into visible strands, fiber bundles, and individual fibers. But then those visible strands, bundles, and fibers will continue to split into microscopic fibers, bundles, and strands. The splitting can continue on to minute levels of microscopic levels of detection. This process is unique to asbestos and is why airborne asbestos is such a problem. The fibers can become so small that they remain airborne longer and pass undetected by the respiratory dust defenses.

Physical characteristics differentiate the serpentine and amphibole forms. Serpentines divide into curly, wavy fibers that show little resistance to being bent or spiraled. Amphibole fibers are needlelike shards that show great resistance to being bent or curled. Serpentines are like man-made wool in appearance, where amphiboles are like man-made fiberglass.

In addition to the two forms, there are three main types of asbestos: chrysotile, amosite, and crocidolite. Chrysotile asbestos is serpentine and amosite and crocidolite are amphibole. Chrysotile is the chief commercial asbestos today. Amosite is used in insulating materials and crocidolite is used for making asbestos-cement products.

Canada is a chief producer of asbestos, which has some of the largest asbestos mine fields in the world. Other producers are Russia, Zimbabwe, the Republic of South Africa, Cyprus, and the United States of America.

Asbestos is a potent carcinogen, that is, a cancer-causing substance, and is a serious health hazard. It is the known cause of pleural plaques, asbestosis, mesothelioma, and causes cancers of the lung, esophagus, and colon. Diseases caused by asbestos have a long latency period, usually taking ten to forty years before showing any symptoms of the disease. This is especially apparent today, when people who worked with installing asbestos as insulation and other materials in the 1970s are just now coming to realize that they are developing cancer at alarming rates.
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