<b><i>Purpose:</i></b> In the current study, we tried to analyze the diagnostic value of HSP90α expression during the course of disease in patients treated with and without surgery. <b><i>Methods:</i></b> Three hundred and twelve patients with lung cancer who referred to Qinhuangdao First Hospital from June 2016 to March 2021 were selected as the experimental group and 160 healthy individuals subjected as the control group in this cohort study. The ELISA method was used to detect the expression level of plasma HSP90α. <b><i>Results:</i></b> We observed significant differences in the level of HSP90α in pathologic type, differentiation degree, stage, and presence of lung, liver, and bone metastasis; HSP90α was significantly higher in non-small cell lung carcinoma in comparison with small cell lung carcinoma, especially in lung adenocarcinoma. Our results demonstrated that HSP90α at 71.45 ng/mL had a sensitivity of 66.3% and a specificity of 95.0% for diagnosing lung cancer. Also, we observed that the HSP90α expression was significantly increased prior to lung cancer relapse in patients treated with chemoradiotherapy and surgery. <b><i>Conclusion:</i></b> Serum level of plasma HSP90α could be a reliable biomarker in diagnosing lung cancer and its subtypes and might be a valid biomarker for predicting lung cancer relapse in patients treated with chemoradiotherapy and surgery.
56P Plasma circulating ctDNA: Potential biomarker in non-small cell lung carcinoma and clinical significance