KJ: Kalau jadi presiden Umno, saya pecat Lokman sebab IQ tahap lobak









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Mesothelioma was virtually unknown until the 20th century. After decades investigating the disease, medical researchers identified the cause: Asbestos exposure. Mesothelioma rates rose as industries expanded the use of asbestos.
Diagram showing how asbestos exposure affects the body
Diagram of mesothelioma causes by location.
Research studies proved inhaling or swallowing microscopic asbestos fibers can start a chain reaction that leads to several types of cancer. The toxic dust can also cause asbestosis, an incurable breathing disorder.
In March 2009, the International Agency for Research on Cancer (IARC) reconfirmed asbestos exposure as the leading cause of mesothelioma. All forms of asbestos cause the disease.
Two years later, the IARC presented an update on the link between asbestos and cancer at a World Health Organization conference in Spain. They explained the scientific evidence has strengthened over time. There is now overwhelming proof asbestos is carcinogenic to humans, regardless of the type or fiber length.

Main Risk Factors for Mesothelioma

  • Working at an asbestos mine or asbestos-processing plant
  • Working in a high-risk occupation such as construction or heavy industry
  • Serving on military ships or facilities built with products containing asbestos
  • Living in a residential area near an asbestos mine or contaminated site
  • Disturbing asbestos products during a home renovation without proper safety measures

How Does Mesothelioma Develop?

Once asbestos is inhaled, the body has a hard time getting rid of the sharp fibers.
These fibers eventually build up in the lungs or abdomen over time. After many years, these fibers may cause cancerous changes.
Cancer starts in mesothelial cells, which comprise the protective membranes that cover the lungs, abdomen and heart.
Four stages of mesothelioma tumors forming on the lungs.
Tumors tend to form a sheath around the affected lung.

Possible Mechanisms for Asbestos-Related Tumor Development

  • Inflamed Cells: Fibers inflame and irritate mesothelial cells, which leads to irreversible scarring, cellular damage and cancer.
  • Genetic Changes: Fibers enter mesothelial cells and disrupt their life cycle, causing genetic changes that lead to cancer.
  • Cancerous Mutations: Asbestos causes the production of free radicals, which are molecules that damage DNA and cause healthy cells to mutate.
  • Uncontrolled Growth: The fibers trigger the production of oncoproteins, which block genes that protect cells from growing uncontrollably and forming tumors.
Mesothelioma has a dose-response relationship to asbestos, which means higher doses of asbestos exposure lead to a greater risk of developing mesothelioma or another asbestos-related disease.
In 2012, mesothelioma specialist Dr. Michele Carbone, director of thoracic oncology at the University of Hawaii Cancer Center, co-wrote a scientific article detailing multiple ways asbestos may damage the body.

DNA Damage Caused by Asbestos Fibers

  • Chronic Inflammation: Fibers can inflame and irritate mesothelial cells, which leads to irreversible scarring, cellular damage and cancer.
  • Cell Life-Cycle Disruption: Fibers can enter mesothelial cells and disrupt their life cycle, causing genetic changes that lead to cancer.
  • Cancerous Mutations: Asbestos can cause the production of free radicals, which are molecules that damage DNA and cause healthy cells to mutate.
  • Uncontrolled Growth: Asbestos fibers can trigger the production of oncoproteins, which block genes that protect cells from growing uncontrollably and forming tumors.
Every healthy cell has genes that regulate growth and safeguard against cancer.
Once asbestos blocks this function, cells can divide uncontrollably, causing malignant tumors to form locally and possibly metastasize — spreading throughout the body and forming metastatic tumors.
Metastatic tumors develop relatively late in the course of mesothelioma but may be a patient’s main source of symptoms.
While all types of asbestos cause mesothelioma, certain types, such as crocidolite and amosite, are especially dangerous. Researchers believe the varying chemical composition of the different asbestos types makes some asbestos more carcinogenic than others.
The majority of people who work with asbestos will not develop a disease, but individual factors might lead to a diagnosis. For example, genetics play a role in mesothelioma development. And smoking cigarettes can increase the risk of asbestos-related lung cancer.
Apart from the risk factors associated with asbestos, a few other factors could increase your risk of developing mesothelioma:
  • Exposure to other fibrous minerals such as erionite.
  • Exposure to radiation.
  • Receiving a polio vaccine between 1955 and 1963 that was contaminated with simian virus 40 (SV40).
  • Genetic mutations that increase the likelihood of developing cancer.
Mesothelioma is more common in men than women and it rarely affects people younger than 45. This is because mesothelioma often takes decades to develop, and men are more likely to work in jobs where asbestos exposure occurs.

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