INHIBITION OF RAT MAMMARY CARCINOGENESIS BY INOSITOL HEXAPHOSPHATE (PHYTIC ACID) - A PILOT-STUDY

Since phytic acid (inositol hexaphosphate, InsP6) and inositol (Ins) h ave been demonstrated to have anti-tumor and anti-cell proliferative a ction in several experimental models of carcinogensis, in a pilot stud y we have examined their effect on 7,12-dimethylbenz(a)anthracene (DMB A)-induced rat mammary tumor model. Starting a week prior to induction with DMBA. the drinking water of female Sprague-Dawley rats was suppl emented with either: 15 mM InsP6, 15 mM Ins, or 15 mM InsP6 + 15 mM In s; a control group received no inositol compounds. Animals (55-day-old ) were given a single dose of DMBA (20 mg) in 1 ml of sesame oil by or al intubation. Four additional groups not receiving DMBA, but drinking tap water, InsP6, Ins, or InsP6 + Ins of the same molarity as experim ental groups were observed for the duration of the study to monitor fo r any putative toxicity following this long-term treatment. As opposed to the DMBA-only group, rats treated with InSP6 +/- Ins showed a 48% reduction in the number of tumors/tumor bearing animal (tumor multipli city) and a 40% reduction in the number of tumors/rat. In contrast to 20% rats in DMBA-only group, only 0-8% animals in the treatment group had 5 or more tumors. Likewise, the tumor incidence was reduced by 19% in InsP6 +/- Ins as compared to control untreated animals. The tumors in the treated groups were also 16% smaller in size. Data from this p ilot study suggest that in addition to being effective against colon c ancer, InsP6 +/- Ins may be protective against mammary carcinoma as we ll; additional studies are however warranted.