Nonlinear tumor evolution from dysplastic nodules to hepatocellular carcinoma

Area of Science:

• Hepatology
• Genomics
• Cancer Biology

Background:

• Dysplastic nodules (DNs) are premalignant lesions in cirrhotic livers.
• Understanding the molecular evolution from DNs to hepatocellular carcinoma (HCC) is crucial for early detection and treatment.

Purpose of the Study:

• To investigate the genetic relationship between dysplastic nodules and concurrent hepatocellular carcinoma in patients with cirrhosis.
• To elucidate the molecular pathways involved in hepatocarcinogenesis.

Main Methods:

• Whole-exome sequencing (WES) was performed on DNs and HCCs from four patients with multifocal nodular lesions.
• Genomic profiles, including somatic single nucleotide variations (SNV) and copy number variations (CNV), were analyzed and compared.
• Phylogenetic analysis was used to infer the evolutionary relationships between DNs and HCCs.

Main Results:

• The number and variant allele frequency of somatic SNVs were identical in DNs and concurrent HCCs within each patient.
• Somatic SNVs and CNVs showed limited conservation between DNs and HCCs.
• Phylogenetic analysis revealed a nonlinear segregation pattern, suggesting independent development.

Conclusions:

• Somatic mutations in dysplastic nodules may arise independently from concurrent hepatocellular carcinoma.
• The findings support a nonlinear model for hepatocarcinogenesis, where DNs and HCC develop separately rather than through direct linear progression.
• This suggests that not all dysplastic nodules progress to HCC through a single clonal evolutionary path.