Clinical Significance of Monitoring Circulating Free DNA and Plasma Heat Shock Protein 90alpha in Patients with Esophageal Squamous Cell Carcinoma

Background: Esophageal squamous cell carcinoma (ESCC) is the predominant histological type of esophageal cancer in China and has an extremely poor prognosis. Circulating free DNA (cfDNA) and plasma heat shock protein 90alpha (Hsp90a) are two novel noninvasive biomarkers for diagnosis and prognostic prediction of several types of cancer. However, to the best of our knowledge, the roles of the two biomarkers in ESCC are still unknown. Methods: Here, we recruited 93 primary ESCC patients and detected plasma concentrations of the two markers at different time points, including 1-3 days pre-chemotherapy, 1-7 days pre-surgery and 7-14 days post-surgery. Baseline concentrations of the two markers were associated with main characteristics of ESCC patients which were collected at first diagnosis. Correlation between the two markers and traditional serum biomarkers at baseline was also examined. Furthermore, dynamic changes of the cfDNA and Hsp90 alpha concentrations among different time points and the potential clinical significance were assessed. Results: Consequently, there was no significant association between baseline concentrations of the two markers and clinical features. Especially, cfDNA demonstrated stronger correlation with other circulating biomarkers than Hsp90 alpha at baseline level. Importantly, both cfDNA and Hsp90 alpha concentrations were significantly increased after surgery. Kaplan-Meier survival analysis showed that a change in concentration of cIDNA (Delta cfDNA) but not Hsp90 alpha (Delta HSP90 alpha) between pre-surgery and post-surgery had significant effect on the overall survival of surgical patients with ESCC. Conclusion: Thus, Delta cIDNA evaluation could be a promising prognostic marker for surgical ESCC patients. Our findings may improve the understanding of the function of cIDNA and Hsp90 alpha in ESCC.