When you’re dealing with an extremely rare form of cancer like malignant mesothelioma, it would make sense to assume that everybody with the disease will receive similar treatments and experience similar progression of their disease. But even in a condition that strikes just 3,500 people per year, there can be wide variations, and French researchers have just confirmed that one of the biggest difference-makers is the presence or absence of a protein called PD-L1 in their tumors.
PD-L1 Protein Helps Tumors Hide From Immune System
When the body detects any kind of foreign cell — whether a mesothelioma cell or a bacteria or virus — the immune system kick into action and attacks it. But what French researchers have found is that when an individual patient’s tumors contain high levels of the protein PD-L1 (programmed death ligand 1), the immune system seems to bypass those cells. This is because PD-L1 effectively hides the tumors from detection.
In a study looking at the tumors of over 200 mesothelioma patients previously diagnosed with epithelioid, sarcomatoid and biphasic subtypes, they found that those with tumors containing higher levels of PD-L1 experienced the shortest survival times: those with more than 1% of their tumor cells expressing PD-L1 lived a median of 12.3 months, while those whose tumors had les PD-L1 lived a median of 22 months. They also found the protein was more likely to be present in those with the rare subtypes, which are the sarcomatoid and biphasic types.
PD-L1 Is A Target of Many Mesothelioma Treatments
As researchers confirm PD-L1’s role in both shorter survival and faster return of mesothelioma tumor growth after treatment in mesothelioma patients, they also are working to develop medications and treatments that specifically target the protein. Notably, three of the most promising cancer treatment drugs — Keytruda (pembrolizumab), Opdivo (nivolumab) and Bavencio (avelumab) — are all PD-L1 blockers that work to make mesothelioma cancer cells visible to the immune system.
If you or someone you love has been diagnosed with malignant mesothelioma, each study that reveals more about the illness is a step towards extended survival. For information about available treatments, contact the Patient Advocates at Mesothelioma.net at 1-800-692-8608.