Biaoxue R, et al. - Researchers determined the level of Hsp90-beta in malignant pleural effusion (MPE) of patients with lung cancer. They also investigated the clinical value of Hsp90-beta as a potential tumor marker for differential diagnosis of lung cancer-related pleural effusion. For measuring the level of Hsp90-beta, they used enzyme-linked immunosorbent assay. They also used receiver operator characteristic curve. Findings revealed a correlation of increased Hsp90-beta in MPE with malignant biological behavior of lung cancer patients. This implied that, for differential diagnosis of pleural effusion caused by lung cancer, the level of Hsp90-beta could be used as a tool of referential value.