Background: The published sensitivity of cytological examination for malignant pleural effusions (MPE) ranges between 50% and 71%. The Epi proLung® BL Reflex Assay (Epigenomics AG, Berlin, Germany) has been reported as being highly sensitive and specific for lung cancer using bronchial aspirates. We hypothesize the assay to be of use in the detection of MPE.
Materials and methods: To test our hypothesis, we performed a retrospective cohort study on pleural effusion specimens of 1,270 patients (472 cases and 798 controls). The assay is based on quantification of methylated Short Stature Homeobox gene two (SHOX2) DNA in the specimen measured via multiplex real-time Polymerase Chain Reaction (PCR) on bisulfite-converted DNA.
Results: Surprisingly, the assay detects metastases of lung cancer, as well as metastases of other malignant tumours. With a re-defined cut-off criterion, the test achieved a sensitivity of 39.5% with a specificity of 96.2%.
Conclusion: This assay is able to detect MPE while not limited to the detection of lung cancer.
Keywords: Cytology; DNA methylation; SHOX2; biomarker; breast cancer; lung cancer; malignant tumour; pleural effusion; quantitative methylation-specific PCR.