ANTIPROLIFERATIVE EFFECT OF FERMENTED MILK ON THE GROWTH OF A HUMAN BREAST-CANCER CELL-LINE

In vivo and in vitro studies have shown an antitumor activity of Lacto bacilli in colon cancer, and some epidemiologic studies have indicated a reduced risk of breast cancer in women who consume fermented milk p roducts. We studied the direct effect of milk fermented by five bacter ia strains (Bifidobacterium infantis, Bifidobacterium bifidum, Bifidob acterium animalis, Lactobacillus acidophilus, and Lactobacillus paraca sei) on the growth of the MCF7 breast cancer cell line. Our results sh owed a growth inhibition induced by all fermented milks, even though B . infantis and L. acidophilus were the most effective (85% inhibition after 9 days). The antiproliferative effect was not related to the pre sence of bacteria in fermented milk, and neither whole milk (crude or ultrahigh temperature sterilized) nor its main fractions (lactalbumin or beta-lactoglobulin fraction) affected cell growth. Our findings sug gest the presence of an ex novo soluble compound produced by lactic ac id bacteria during milk fermentation or the microbial transformation o f some milk components in a biologically active form. Although the mec hanism of the antitumor activity is not clear, the present study sugge sts the potentiality offered by fermented milk as producers of compoun ds with antiproliferative activity useful in the prevention and therap y of solid tumors like breast cancer.