The Regeneration Paradox in Liver Cancer: How Chronic Injury Transforms Healing into Carcinogenesis.

Background: The liver presents a fundamental paradox: it possesses unparalleled regenerative capacity yet demonstrates exquisite cancer susceptibility under chronic injury, with 85-90% of hepatocellular carcinoma (HCC) arising from chronic liver disease. Despite decades of research, the field lacks a unifying framework explaining this contradiction. Summary: We propose that HCC arises not from regeneration failing but from regeneration succeeding too long. The identical molecular pathways that safely restore hepatic mass after acute injury become carcinogenic when activated for decades rather than weeks - duration determines destiny. Living donor hepatectomy (60% resection) demonstrates zero cancer risk despite maximal proliferation because activation lasts only 2-4 weeks. Conversely, chronic HCV infection triggers identical responses monthly for 25-30 years, yielding 40-60% cumulative HCC incidence. When regeneration persists chronically, seven corruptions progressively accumulate: division trap (mutational accumulation), selection engine (clonal expansion), memory lock (epigenetic cementing), physical prison (mechanical oncogenesis), immune betrayal (tolerance induction), termination failure (brake inactivation), and senescence trap (SASP-mediated promotion). These develop in parallel and interact synergistically. Clinical evidence validates stage-dependent reversibility: HCV cure at F0-F1 achieves >95% cancer prevention, while cure at F4 cirrhosis provides 70% risk reduction despite irreversible corruptions. Taiwan's HBV vaccination program demonstrates >80% cancer reduction sustained over 40 years when chronic injury is prevented entirely. Key Messages: Duration of pathway activation - not pathway identity - determines whether regeneration remains safe or becomes carcinogenic. Understanding HCC pathways as regenerative pathways stuck "ON" enables rational therapeutic strategies through corruption-specific targeting. Early intervention prevents >95% of cancers; even late intervention at cirrhosis achieves 70% benefit. The regeneration paradox transforms HCC from mysterious misfortune into predictable consequence, enabling precision prevention and treatment.