Intestinal Flora and Cancer Control: Inhibitory Effect of Oral Administration of Lactobacillus casei in a Model of Hepatic Metastasis of Rat

Studies on the antimetastatic activity of orally administered Lactobacillus casei (L. casei) were performed using an experimental model of hepatic metastasis. Orally administered L. casei (BLP) significantly inhibited liver tumor colonization, and lowered the incidence of hepatic metastasis the most at a dose of 100mg/kg per day. Furthermore, liver tumor colonization after inoculation with AH60C tumor cells was significantly inhibited in all the groups given BLP, particularly in the groups which were given BLP orally before tumor inoculation (P < 0.01). However, BLP had no significant effect on the rate of incidence of hepatic metastasis. These results strongly suggest that L. casei has an antimetastatic effect, and that it may be of therapeutic use for the prevention of micrometastasis after surgery.