Mesothelioma Study Investigates Role of Mesothelin Gene in Cancer Development

Mesothelioma Mesothelioma Mesothelioma
Friday, August 13th, 2010

Japanese researchers recently investigated the mechanism by which mesothelin is expressed in malignant mesothelioma. The study was published in the peer-reviewed medical journal Human Pathology.

Mesothelioma is a rare cancer almost exclusively caused by asbestos exposure. Because there is no cure for this disease, the mesothelioma life expectancy for most patients ranges between four and 18 months after diagnosis. Although no cure currently exists, some mesothelioma patients are diagnosed early enough to qualify for a combination of aggressive therapies, such as surgery, chemotherapy and radiation. The combination of therapies, known as multimodality therapy, currently has the best chance of extending a patient’s life expectancy.

Authors of the study explain, “Gene methylation leads to malignant progression in some tumors… [Malignant mesothelioma] is histologically divided into 3 subtypes, that is, the epithelioid, sarcomatoid, and biphasic types, and it was shown that mesothelin expression was restricted to the epithelioid type and the epithelioid component of the biphasic type of MM [malignant mesothelioma]. However, its regulatory mechanism of expression has not been clarified.”

A total of 118 lung specimens were studied, including 39 MM, 41 lung carcinoma, 26 nonneoplastic pulmonary lesions, and 12 normal lung tissue samples. The specimens were tested for expression of mesothelin through immunohistochemistry testing, along with the methylation status of 20 sites in the promoter of the mesothelin gene (MSLN).

Results confirmed that mesothelin was expressed in the epithelioid subtype and the epithelioid part of the biphasic subtype. However, mesothelin expression was not found in either the sarcomatoid subtype nor the sarcomatous part of the biphasic type. The MSLN promoter was significantly hypomethylated in the MM specimens regardless of its subtype when compared with the other pulmonary lesions and normal lung tissue samples.

The researchers concluded, “These findings suggested that hypomethylation of the MSLN promoter may be specifically associated with the formation of MM, regardless of its expression status, and that the expression of mesothelin protein was lost in the sarcomatoid type by some unknown posttranscriptional regulatory mechanism.”

Additional information on mesothelioma may be found through the Mesothelioma Center.

source: www.asbestos.com