Relationship between hepatocellular carcinoma circulating tumor cells and tumor volume

Abstract Background Microfluidic platforms have demonstrated the ability to isolate rare circulating tumor cells from a wide variety of cancers. Our group has recently shown the ability to isolate circulating tumor cells (CTCs) from hepatocellular carcinoma (HCC) patients using a hematopoietic cell depletion microfluidic platform. However, the relationship of CTC generation and HCC progression is still not well understood. Tumor size is often used as a clinical prognostic factor, but there has been an inconsistent relationship of tumor size and metastatic recurrence. Characterizing the relationship of primary tumor size and CTCs would provide a better understanding of HCC tumor size and metastatic potential. Results CTCs in a cohort of HCC patients with quantitative tumor volume analysis was performed to determine if there was a relationship of tumor size to CTC generation. A total of 24 tumor volumetric analyses were used in this study, and a cutoff of 25 cc was used to create a low and high tumor volume group (median 5.56 vs 108 cc; p < 0.0001). Using an antigen agnostic microfluidic CTC isolation platform and immunofluorescent staining for cytokeratin and glypican-3, CTCs were detected in 18 of 22 (82%) HCC patients. CTCs/mL of blood did not correlate with either tumor volume or serum AFP. Interestingly, CTCs were found to be significantly higher in small compared to large volume tumors (median 18.5 vs 5 CTCs/mL; p = 0.0454). Conclusion Altogether, HCC CTCs provide additional data about the tumor independent of standard imaging and blood biomarkers, and there may be biological differences in small volume tumors that facilitate CTC entry into the blood stream. This has implications for HCC CTCs as a biomarker for predicting recurrence and as an early detection platform