The water extract of lac, known as a lac dye, is a natural pigment, which is commonly used as food colorant.22 The main components of lac water extract are laccaic acids, a series of hydroxyanthraquinoid derivatives, namely laccaic acid A, B, C, and E.21,23 Although various pharmacological activities of either lac dye or the laccaic acids have been reported, including anti-cancer, anti-microbial and anti-genotoxic activities,24–26 the detailed mechanism of the actions of lac dye or the laccaic acids is not well-understood. This evidence concerns the gene LCT and cancer.