Clinical significance of serum dynamics of HSP90a level in esophageal squamous cell carcinoma patients treated with definitive chemoradiotherapy

We evaluate whether the change of heat shock protein 90a (HSP90a) level before and after definitive chemoradiotherapy (CRT) in esophageal squamous cell carcinoma (ESCC) affects tumor response and overall survival (OS). This study aimed to investigate the role of HSP90a reduction ratio after CRT. Correlations between pre-CRT HSP90a levels and the tumor response to CRT were analysed. Patients were divided into three groups (Group 1: Serum HSP90a levels pretreatment CRT less than 124 ng/mL; Group 2: pre-CRT HSP90a of 124 ng/mL or more with HSP90a reduction ratio of 65% or more; Group 3: pre-CRT HSP90a of 124 ng/mL or more with HSP90a reduction ratio less than 65%), and their oncologic outcomes were compared. The rates of good response in HSP90a low (pre-CRT HSP90a ≤ 124 ng/mL) and high groups (pre-CRT HSP90a ≤ 124 ng/mL) were 67.3% (68/101) and 37.78% (20/79), respectively (P= 0.004). The rates of good response were significantly higher in Group 1 than in Groups 2 and 3 (58.5% vs. 46.0% and 27.8%, respectively; P= 0.013). The results from statistical analysis indicated that the tumor response was significantly associated with the serum levels of pre-CRT HSP90a and HSP90a Group (P< 0.05). The OS rate was not different between Groups 1 and 2 but was significantly lower in Group 3. HSP90a Group were independent prognostic factors for OS. HSP90a levels could be of clinical value as a predictor of response to CRT HSP90a reduction ratio might be an independent prognostic factor for in ESCC patients treated with definitive CRT.