A protein known as CD90, which has been suggested as a possible biomarker for malignant pleural mesothelioma (MM), may not contribute to the reliable diagnosis of this disease after all, according to a study published in the journal Pathology and Oncology Research.
The study, “The Role of CD90 in the Differential Diagnosis of Pleural Malignant Mesothelioma, Pulmonary Carcinoma and Comparison with Calretinin,” was conducted by a research team at Inonu University, Turkey.
MM displays various tissue patterns and appearances with different variations, and the most common include epitheloid, sarcomatoid, and biphasic types. Distinguishing between the epithelioid type of malignant pleural mesothelioma and lung adenocarcinomas is rather difficult, and even the most experienced pathologists need a wide panel of tissue markers to perform this task.
Although several markers, including the protein calretinin, are effective in diagnosing many mesotheliomas, new and more specific markers are needed to assist in the diagnosis of more difficult cases.
The team at Inonu University, led by Nurhan Sahin, sought to investigate whether the protein CD90 could be used as a reliable marker for differential diagnosis of MM and lung carcinoma, as well as for its prognostic value in comparison to calretinin.
Researches analyzed the presence of both proteins in 30 samples of MM, 30 samples of pulmonary adenocarcinoma, and 30 samples of pulmonary squamous cell carcinoma.
Results indicated that calretinin was positive in 20 MM samples (64.5 percent) and negative in 10 (32.3 percent), whereas CD90 was positive in 25 samples (80 percent) and negative in 5 (16 percent).
But although these results suggested that CD90 was a valuable marker to diagnose mesothelioma, the researchers found that it couldn’t differentiate MM samples from those of other lung diseases. Indeed, while all samples of adenocarcinoma and squamous cells carcinomas were negative for calretinin, CD90 was detected in 19 (63.6 percent) and 22 (73 percent) of those disease samples, respectively.
These results led the authors to conclude that “in contrast to reports from previous studies that have suggested that CD90 can be used as a new marker for the differential diagnosis of mesothelioma, we found its specificity to be 36.6% … in this study and these data suggest that CD90 has no place in the differential diagnosis of mesothelioma and pulmonary carcinoma due to its low specificity.”