Fig 1. Effect of vitamin A supplementation on tumor multiplicity.

BALB/cAnNCr-nu/nu female mice, aged 6 to 8 wks, were randomly divided into two groups. The first group consumed the control diet, containing 2,400 IU vitamin A/kg diet. The second group consumed a diet supplemented with 200,000 IU vitamin A/kg diet. The mice consumed these diets ad libitum for one month prior to surgery. To generate metastases, the mice were intrasplenically injected with 2 × 10⁶ HCT-116 cells in 50 μl of magnesium and calcium-free HBSS. Following surgery, the mice continued to consume their respective diets for five weeks. After five weeks, all mice were sacrificed and their livers examined visually for the presence and number of metastases. (A) Livers representing tumor multiplicity scores of 11 (left) and 1 (right). (B) Representative slides showing negative (left) and positive (right) staining for CK20. Arrow indicates metastatic tumor. Scale bar is 1.0 mm. (C) Data shown are hepatic tumor score per mouse, mean ± SEM, n=14. Scoring scheme is shown in Table 2. *Significantly different from control (P < 0.05).