Washington, Apr 21: Researchers from Fox Chase Cancer Centre have found that pregnancy hormone hCG protects against breast cancer even in short-term treatments.

Lead researcher Dr Johana Vanegas showed that presence of human chorionic gonadotropin (hCG), a hormone produced by the placenta to maintain the early stages of pregnancy offers protection against breast cancer.

She said that even a much shorter exposure to hCG could prevent breast cancer in rats.

During the study, Vanegas and her colleagues studied virgin female rats, which had been divided into four groups: a control group, which did not receive hCG, and three groups that received hCG for five, ten or fifteen consecutive days. Following the treatment, each rat received a single dose of a breast cancer-inducing agent.

It showed that rats exposed to hCG over a 21 day period (the length of rat pregnancy), are far less likely to develop breast cancer when exposed to a known carcinogen.

90.9 percent of the rats in the control group developed breast tumours, compared to 71.4 percent, 57.1 percent, and 15.4 percent in the five, ten and fifteen day-treated animals, respectively.

In addition, the average tumour size was also smaller in all the animals that received any of the three hCG treatments.

Vanegas suggests that one of the most effective ways to prevent breast cancer is through a full-term pregnancy at an early age.

"The ability to replicate the naturally protective effects of pregnancy against breast cancer will hold a significant public health value," said Vanegas.

"In order to translate our finding into humans, a clinical trial with hCG as a preventive agent against breast cancer, is already ongoing in pre-menopausal women with no previous pregnancy," she added.

The study was presented at 100th Annual Meeting of the American Association for Cancer Research. (ANI)