Cell-free junctional DNA fragment from hepatitis B virus integration in HCC for monitoring postresection recurrence and clonality.

Abstract

4090 Background: About one-third of patients suffer tumor recurrence within the first year after surgical resection of HCC. Early recurrence compromised their overall survival. Timing detection of HCC recurrence and its clonality is required to implement therapeutic trials appropriately. This study examined the virus-host chimera DNA (vh-chimera DNA), generated from junctions of HBV integration in HCC chromosome and released into blood, as a potential circulating biomarker for this clinical setting. Methods: We established a capture-next generation sequencing (NGS) platform to identify the HBV integrations in 50 resected HBV-related HCC. For individual HCC, the major clonal HBV integration sites were chosen to design specific primers for droplet digital PCR (ddPCR) to detect and quantify the vh-chimera DNA in plasma samples, collected either just before surgery or two months after surgery. Levels of vh-chimera DNA were then correlated with baseline HCC size or recurrence in one-year follow up. Results: We succeeded in detecting HBV integrations in the HCC from 44 out of 50 HBV-related HCC patients (88%). The copy number of vh-chimera DNA in plasma at surgery from 42 patients correlated with tumor sizes, with the detection limit at 1.5-2 cm. Among the plasma collected 2 months after surgery, 26.2% of samples contained the same HCC signature vh-chimera DNA as baseline plasma, indicating a possible residual tumor. Consistently, 81.8% of them suffered HCC recurrence within one year. The signature vh-DNA in the plasma suggested the majority of recurrences coming from the original HCC clones, whereas 2 from de novo ones. Conclusions: This study supported vh-chimera DNA as a new circulation marker for detecting the existence of most HBV-related HCC. This new biomarker may complement AFP to help detect residual or recurrent HCC and their clonality after curative therapies.