Whole-genome sequencing reveals the evolutionary trajectory of HBV-related hepatocellular carcinoma early recurrence

Patients with hepatocellular carcinoma(HCC)have poor long-term survival following curative resection because of the high rate of tumor early recurrence.Little is known about the trajectory of genomic evolution from primary to early-recurrent HCC.In this study,we performed whole-genome sequencing(WGS)on 40 pairs of primary and early-recurrent hepatitis B virus(HBV)-related HCC tumors from patients who received curative resection,and from four patients whose primary and recurrent tumor were extensively sampled.We identified two recurrence patterns:de novo recurrence(18/40),which developed genetically independently of the primary tumor and carried different HCC drivers,and ancestral recurrence(22/40),which was clonally related to the primary tumor and progressed more rapidly than de novo recurrence.We found that the recurrence location was predictive of the recurrence pattern:distant recurrence tended to display the de novo pattern,whereas local recurrence tended to display the ancestral pattern.We then uncovered the evolutionary trajectories based on the subclonal architecture,driver-gene mutations,and mutational processes observed in the primary and recurrent tumors.Multi-region WGS demonstrated spatiotemporal heterogeneity and polyclonal,monophyletic dissemination in HCC ancestral recurrence.In addition,we identified recurrence-specific mutations and copy-number gains in BCL9,leading to WNT/β-catenin signaling activation and an immuneexcluded tumor microenvironment,which suggests that BCL9 might serve as a new therapeutic target for recurrent HCC.Collectively,our results allow us to view with unprecedented clarity the genomic evolution during HBV-related HCC early recurrence,providing an important molecular foundation for enhanced understanding of HCC with implications for personalized therapy to improve patient survival.