Causes of Mesothelioma Cancer

Causes of Mesothelioma Cancer

An overwhelming body of scientific and medical evidence has proven that the primary cause of malignant mesothelioma is exposure to asbestos. The exact method by which asbestos causes mesothelioma is still being researched, but medical professionals have a number of theories:

Asbestos causes irritation and inflammation of mesothelial cells, which results in irreversible scarring, cellular damage, and eventually cancer.Asbestos fibers enter cells and disrupt the function of cellular structures that are essential for normal cell division, causing cellular changes that lead to cancer.
Asbestos causes the production of free radicals. These molecules damage DNA, and cause cells to mutate and become cancerous.

The presence of asbestos causes cells to produce oncoproteins. These molecules cause mesothelial cells to ignore normal cellular division restraints, and s can lead to the development of cancer.

The element that ties each theory together is the fact that asbestos results in cellular damage. This causes cells to lose control over normal cell cycles and results in uncontrollable division. Healthy cells follow cycles of cell division that ensure tissues do not grow and duplicate beyond normal conditions - in cancerous cells, these restraints are lost.

In cases of mesothelioma, the result of the cellular damage is that membranes in the affected location begin to thicken, and fluid builds up in the spaces between membrane layers. As cancer cells continue to divide and pile on top of one another, tumors begin to form. The uncontrolled division of cancer cells results in the impaired function of the body's organs and systems (primarily due to factors such as internal pressure caused by the growth of tumors, and the reduction of essential nutrients for organs), resulting in a number of symptoms.

Malignant Mesothelioma Cell Types

Malignant Mesothelioma Cell Types

A malignant mesothelioma tumor may be made up of three different cell types:
Epithelial Cells – Epithelial cells appear the most frequently in malignant mesothelioma tumors, and this subtype accounts for about 50 percent of cases. These cells, which are uniform and sharply defined, feature prominent nuclei and often form complex branching patterns.
Sarcomatoid Cells – These spindle-shaped cells typically lack strong characteristics, occurring in approximately 30 percent of reported malignant mesothelioma cases.
Biphasic Cells – A malignant mesothelioma tumor is considered biphasic when both epithelial and sarcomatoid cells are present and each type accounts for at least 10 percent of the mass. Biphasic (mixed) cells are present in around 20 percent of all malignant mesothelioma reports.

Histological classifications are commonly used in developing a prognosis and treatment plan for malignant mesothelioma patients. Although the life span associated with malignant mesothelioma can be short, the subtype can account for differences in life expectancy ranging up to 200 days.

Of the subtypes, mesotheliomas involving epithelial cells are typically most responsive to treatment, resulting in a better prognosis. Sarcomatoid cells are the most stubborn when treated, and some surgeons do not consider sarcomatoid tumors as eligible for resection. Biphasic cells are also considered less responsive to treatment than epithelial.

Diagnosing what type of malignant mesothelioma a patient has can be challenging. One contributing factor is that it can be difficult to differentiate mesothelioma from adenocarcinoma, a cancer originating in glandular tissue, on small tissue specimens.