Study: Mesothelioma Patients with CD70 Protein Have Worse Prognosis
An international team of pathologists has identified a new protein often found on pleural mesothelioma tumor cells.
The discovery could lead to a more accurate prognosis for patients and future treatment advances.
Researchers found for the first time that mesothelioma patients expressing higher levels of the CD70 protein typically experience a much shorter survival, regardless of cell type or treatment type.
“These markers might be useful for MPM [malignant pleural mesothelioma] prognostic evaluations, as well as targeted therapeutics,” the study authors wrote. “Further analyses in syngeneic mouse models demonstrated possible roles for CD70 in immune evasion.”
The Journal of Pathology published the study in December 2019.
Researchers at the Aichi Medical University School of Medicine in Nagakute, Japan, led the study.
Doctors from Poland, Germany and the United States, including those at the National Cancer Institute, also contributed.
Higher Expression Means Shorter Survival
Researchers found that 20% of the mesothelioma tumor cell samples expressed high levels of CD70.
Those patients with the elevated CD70 expression had a median survival of just 6.5 months, compared to 18 months for those who did not overexpress CD70.
The protein involvement may help explain the significant differences in survival times, and how patients respond differently to the same treatments. The issues have puzzled mesothelioma specialists for years.
An overexpression of CD70 previously has been studied in cases of renal cell carcinoma and glioblastoma, an aggressive form of brain cancer. In both cancers, the presence of the CD70 overexpression has been linked to poor clinical outcomes and rapid tumor-cell proliferation, the authors wrote.
First Study of CD70 in Mesothelioma Patients
This latest study involved 172 mesothelioma tumor samples, including 12 with the sarcomatoid cell type, 15 biphasic and 145 epithelioid, the mesothelioma cell type that responds best to treatment.
Researchers in the study identified several different proteins that already have been known to incite anti-tumor immune responses in other cancers.
“The expression of CD70 and CD27, as well as their correlations with patient survival, has never been studied in MPM patients,” the authors wrote. “Our findings suggest that the CD70-CD27 pathway enhances the malignant phenotypes of MPM and diminishes anti-tumor immune response.”
The average age of patients used in the study was 62.9 for those testing positive for CD70 expression and 58.3 for participants who were negative for CD70.
The study also used in-vitro experiments with mouse models that confirmed the protein involvement enhanced the invasiveness of the mesothelioma cells.
The study did not look at patient history regarding the amount of asbestos exposure which occurred or whether they smoked.
“The molecular and animal studies demonstrated that CD70 worsened the prognosis of MPM patients via enhanced invasiveness and immune evasion,” the authors concluded.