Mesothelioma most often develops in the lining of the lungs and pleural cavity, and is well known for its association with the carcinogen asbestos.
In fact, the late Hollywood actor Steve McQueen is known for having developed mesothelioma after years of asbestos exposure while in the military.
That said the vast majority of mesothelioma cases stem from asbestos exposure.
Asbestos is a mineral that was widely used as construction material in everything from paint to insulation to roofing tiles because it has strong fibers that were resistant to fire and served as good insulation.
Asbestos fibers are jagged in shape, and extremely tiny - about 500 times finer than a human
If those tiny asbestos fibers get inhaled over time, they make their way into the interstitial space of the lungs and then slowly make their way over to the epithelial cells of the visceral or parietal pleura - both of which are layers of mesothelium.
The microscopic, jagged asbestos fibers are not metabolized or removed from the lungs — so, unlike smoking, whose risk gets lower after you quit, the risk from asbestos exposure stays with you for life.
The presence of these fibers leads to an inflammatory response and DNA damage.
Eventually, mutations can arise that lead to these epithelial cells dividing uncontrollably, and turning into a tumor.
Over time, small cancerous growths called mesothelial plaques start to cover the visceral pleura over the lungs and the parietal pleural under the chest wall.
Interestingly, these growths start to express a lot of calretinin, a calcium-binding protein, involved in regulating calcium levels within the cell - and this is something that helps to distinguish mesotheliomas from other types of tumors.
Source : @sofiotech