Aneuploidy of chromosome 8 in circulating tumor cells correlates with prognosis in patients with advanced gastric cancer

OBJECTIVE Previous work indicated that aneuploidy of chromosome 8 in circulating tumor cells (CTCs) correlated with therapeutic efficacy for advanced gastric cancer (AGC) patients. In this follow-up study performed on the same population of AGC patients, we investigated whether and how aneuploidy of chromosome 8 in CTCs correlates with patients' clinical prognosis. METHODS The prospective study was performed on 31 patients with newly diagnosed AGC. Previously established integrated subtraction enrichment (SE) and immunostaining-fluorescence in situ hybridization (iFISH) platform was applied to identify, enumerate and characterize CTCs. Quantification of CTCs and analysis of their aneuploidy of chromosome 8 were performed on patients before and after therapy. RESULTS CTCs were measured in 93.5% of AGC patients, and two CTC subtypes with diverse threshold values were identified, multiploid CTCs with the threshold of ≥2 per 7.5 mL and multiploid plus triploid CTCs with the threshold of ≥4, which were found to significantly correlate with poor progression-free survival (PFS) and overall survival (OS). In particular, patients with ≥10% increased multiploid CTCs after an initial 6 weeks of therapy had poor PFS and OS, whereas improved PFS and OS were observed on those who had ≥10% decreased multiploid CTCs. After adjusting for clinically significant factors, ≥10% increased post-therapy multiploid CTCs was the only independent predictor of PFS and OS. CONCLUSIONS Aneuploidy of CTCs correlates with prognosis of AGC patients. Quantitative comparison monitoring multiploid CTCs before and after therapy may help predict improved or inferior prognosis and chemoresistance.