Peretinoin pharmacokinetics study design and change of gene expression profiling. A: Peretinoin pharmacokinetics study design. Twelve patients were enrolled in the study and two groups of 6 patients were randomly administered one of two doses of peretinoin (600 or 300 mg per day) for 8 weeks. A liver biopsy was obtained before the start of peretinoin administration and 8 weeks into the treatment. After the second liver biopsy, oral administration of peretinoin twice daily was resumed for 88 weeks. B: Hierarchical clustering analysis of patients using all expressed genes. Patient numbers (Table 1) and peretinoin dose are listed. Patients with HCC recurrence are shown in red and boxed. There was no significant association between hepatic gene expression and HCC recurrence before starting peretinoin treatment, while distinct clusters of patients were observed after week 8 depending on HCC recurrence.