Fig. 1

The “7-point baseline sample collection protocol” in China. (1) At least four specimens were located at 12 (A), 3 (B), 6 (C), and 9 (D) o’clock at the junction of the tumor and adjacent liver tissues; (2) at least one specimen at the intratumoral zone (E); (3) adjacent peritumoral liver tissues (F, ≤ 1 cm from the tumor capsule) and distant peritumoral liver tissues (G, > 1 cm from the tumor capsule) or the tumor margin [9]