Clapper, Patti, Schweizer and Mason

Mesothelioma researchers have discovered that overexpression of a certain protein can possibly predict chemotherapy results.  Not only do mesothelioma patients with this certain protein anomaly experience better results from chemotherapy, they also experience significantly improved survival rates.

This is good news for many mesothelioma patients.  In spite of new breakthroughs and experimental research, combination mesothelioma treatments of surgery, chemotherapy, and radiation remain the most popular modality for attacking this killer asbestos cancer.  The data uncovered not only helps predict which patients will respond better to chemo in general, but also aids mesothelioma doctors in chosing which types of chemotherapy to use on which patients. 

The protein Dipeptidyl peptidase-4 (DPP4), also known as adenosine deaminase complexing protein 2, called CD26 for short, is found on the surface of certain mesothelioma tumors.  For the purposes of this study, researchers examined retrospective data from 79 mesothelioma cases.  The study encompassed a wide variety of specific types of mesothelioma:

• Malignant pleural mesothelioma
• Malignant peritoneal mesothelioma
• Malignant pericardial mesothelioma
• Epithelioid Mesothelioma
• Sarcomatoid Mesothelioma
• BiPhasic or Mixed Mesothelioma

The study also examined the results from different treatment modalities.  The main population was separated into two groups:  those who underwent chemotherapy and those who didn’t.

Next, each individual case was examined in detail to determine whether or not patients exhibited any specific protein abnormalities.  Researchers found that out of all the malignant pleural mesothelioma patients they examined, nearly 74% of them expressed this CD26 protein on the cell membranes.  All of these patients had been diagnosed with biphasic or epithelioid mesothelioma.  These are the two most common types of mesothelioma with sarcomatoid being the third.  Researchers noted that patients suffering from sarcomatoid mesothelioma lacked this surface protein as a whole and responded poorly to chemotherapy in general. 

When survival rates of the two groups of patients were compared, researchers discovered that patients with this protein who underwent chemotherapy enjoyed a 73% increase in longevity from 10.7 months to 18.6.  While the statistical significant between this 18 month survival rate is great when compared to the overall average of just over 1 year, these specific results reaffirm the deadly and aggressive nature of pleural mesothelioma.  Even with the treatments described in this study, doctors were only able to prolong life on average for an additional 7 to 8 months.

However, as many mesothelioma specialists are quick to point out, any victory against this disease, no matter how small, should be celebrated. 

The research went on to prove that in addition to generally improved prognoses, certain types of chemotherapy worked better on these patients with overexpressed proteins.  Specifically, patients who underwent chemotherapy with non-Pemetrexed regimens lived nearly twice as long as those who underwent therapy with Pemetrexed.