One of the diagnostic challenges for mesothelioma is distinguishing between a malignant disease and a benign one.
A protein called c-MET is another biomarker to help tell the difference.
c-MET is a receptor tyrosine kinase, or a growth factor receptor, encoded by the MET gene. It supposedly has an increased rate of presence in malignant mesothelioma.
A new study shows how often c-MET appears in malignant epithelioid mesothelioma versus “epithelioid mesothelial proliferations,” which are benign tumors formed from mesothelial cells (or benign mesothelioma). The protein is far more prevalent in malignant cases.
How Often c-MET Occurs in Malignant Mesothelioma
Researchers use a staining process to determine if cancerous proteins exist in tissue samples. Two types of cells make up mesothelioma: epithelioid cells and sarcomatoid cells. Each has biomarkers, or proteins, that help pathologists identify them, thus spotting mesothelioma.
Immunohistochemical staining is the most definitive option for diagnosing mesothelioma. It’s also challenging, as some malignant and benign diseases share biomarkers. So finding signs that are unique to malignant mesothelioma is important.
Researchers in this study stained 127 different tissue samples:
- 45 of malignant epithelioid mesothelioma
- 26 of malignant sarcomatoid mesothelioma
- 33 of benign epithelioid mesothelioma
- 23 of benign sarcomatoid mesothelioma
Doctors used a 12-point score to classify the extent of c-MET’s presence in the staining. Scores from 4-6 were moderate and 8-12 were strong. Scores of 1-3 were trace.
The H-score for c-MET was at least moderate in 24 out of 45 (53%) of the malignant epithelioid mesothelioma samples. Sensitivity classified as moderate or strong rose to 76% after pathologists added BAP1 staining, a known biomarker for malignant mesothelioma.
“Overall, experts inferred that it is valid to use moderate/strong c-MET staining to support a diagnosis of epithelioid malignant mesothelioma (versus) an epithelial reactive proliferation,” the report states.
The percentage of a moderate or strong presence was not as high for the benign epithelioid mesothelioma samples. For the sarcomatoid samples, the data isn’t reliable enough to determine between malignant and benign cases.
Why the c-MET Biomarker Can Save Lives
Fortunately, epithelioid mesothelioma is the most common cell type of this cancer. It occurs in at least half and possibly up to 75% of all mesothelioma cases. The emergence of c-MET as a biomarker is relevant for most of the 3,000 Americans each year who get this cancer.
Epithelioid mesothelioma also has the best prognosis of the different cell variations, and early detection of a malignant disease allows patients to undergo curative treatment. The cMET biomarker could play a massive role in helping specialists diagnose malignant mesothelioma earlier and more accurately.
Show Sources & Author
- c-MET immunohistochemistry for differentiating malignant mesothelioma from benign mesothelial proliferations. MDLinx. Retrieved from: https://www.mdlinx.com/journal-summary/c-met-immunohistochemistry-for-differentiating-malignant-mesothelioma-from-benign-mesothelial/6QySShmipCbLo8ZCtnbMg8. Accessed: 09/14/2020.
- About Malignant Mesothelioma. American Cancer Society. Retrieved from: https://www.cancer.org/content/dam/CRC/PDF/Public/8733.00.pdf. Accessed: 10/01/19.