Protein Biomarker for Mesothelioma Linked to Shorter Survival

An international team of scientists has identified a protein biomarker for mesothelioma that appears to shorten survival.

The biomarker is CD70. It belongs to the tumor necrosis factor (TNF) family of proteins. New research suggests that patients who express more of this protein biomarker for mesothelioma have faster-growing tumors that are less likely to respond to treatment.

High CD70 levels have been linked with tumor aggression in some other types of cancer. This is the first time they have been linked to malignant pleural mesothelioma survival. 

CD70 and Mesothelioma Prognosis

Pleural mesothelioma is a highly aggressive type of tumor. It grows on the membranes around internal organs. Mesothelioma rarely responds to standard cancer treatments. People diagnosed with pleural mesothelioma are often given just months to live. 

But some mesothelioma patients live much longer. These patients respond well to treatments like chemotherapy with Alimta or immunotherapy with Keytruda. Some patients, like Australian Paul Kraus, have survived mesothelioma for 20 years or more. 

Scientists have wondered what the difference is between long-surviving mesothelioma patients and those who die early. The new study is the latest to suggest that a protein biomarker for mesothelioma may be part of the reason. 

The Role of a Protein Biomarker for Mesothelioma

All cells receive their instructions through proteins. Different proteins signal cells to grow, divide, and even die. CD70 is just one of many signaling proteins. Researchers believe that it works in close conjunction with CD27 to help regulate immune response to cancer. 

In healthy people, the immune system fights cancer naturally. But the process can malfunction when protein expression is out of balance. 

Researchers at Aichi Medical University School of Medicine in Nagakute, Japan led the study into the new protein biomarker for mesothelioma. The trial included scientists in Germany, Poland, and the US National Cancer Institute. 

They measured protein expression in 172 pleural mesothelioma patients. They found that 20 percent of mesothelioma cells overexpressed CD70.

“Overall survival was significantly decreased in the cohort of patients with CD70-expressing tumour cells,” writes lead author Shingo Inaguma. Experiments in mice showed that high CD70 makes mesothelioma cells more invasive.

In contrast, patients who expressed higher levels of CD27 had better outcomes. 

The researchers conclude that CD70 is a promising protein biomarker for mesothelioma. It could be helpful for determining mesothelioma prognosis. This new information about CD70 could also open the door for more targeted immunotherapy treatments. 

“Collectively, these findings suggest that the CD70-CD27 pathway enhances the malignant phenotypes of MPM and diminishes anti-tumor immune response in patients with these neoplasms,” writes Dr. Inaguma.

Source:

Inaguma, S, et al, “CD70 expression correlates with a worse prognosis in malignant pleural mesothelioma patients via immune evasion and enhanced invasiveness”, October 22, 2019, Journal of Pathology, Epub ahead of print, https://onlinelibrary.wiley.com/doi/abs/10.1002/path.5361