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

PURPOSE: We evaluate whether the change of heat shock protein 90a (HSP90a) level before and after definitive chemoradio-therapy (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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.