Researchers have determined that a molecule found in a pregnancy-specific hormone can actually help block the growth of specific cancers, including Kaposi's sarcoma - an AIDS related cancer with no known cure.

The hormone in question, human chorionic gonadotropin (hCG), is the center of a 20-year-old controversy  as to whether hormones found in pregnant women can be used to fight cancer and AIDS related tumor growth.

In the mid-1990's researchers published a study that showed how crude or partially purified hCG extracted from a pregnant woman's urine could shrink Kaposi's sarcoma tumors. However, the authors of that study later retracted their claim that it was the hCG itself that was attacking these tumors directly, according to a University of Montreal press release.

Now, two decades later, University of Montreal (UM) scientists have announced that they've determined the true compound that was making hCD effective.

The researchers presented these findings on Monday at the 2014 joint meeting of the International Society of Endocrinology and The Endocrine Society in Chicago, Illinois.

Twelve years ago, UM principle investigator Tony Antakly and his team determined that purified hCG did not affect AIDS tumor cells in the same way that the crude hCG did, indicating that the true cancer fighting compound must be eliminated during the purification process. This, the researchers reported, narrowed down their search.

At the end of this decade-long hunt, the researchers are confident that a large molecule they are calling hCG-like inhibitory products (HIP) is involved. This blood and urine-based molecule transforms into a small metabite that can target tissue (such as cancer cells) directly.

However, the researcher remain unsure why this metabite is present in pregnant women, or why it transforms.

"We don't know if it changes only when needed," Antakly said. "Perhaps in cancer, it changes to fight the disease."

The researchers were able to determine in controlled lab settings that HIP metabolite "wiped out the cancer cells completely" in Kaposi's sarcoma cell samples.

Now the team is working on perfecting a synthetic copy of the HIP metabolite, which they hope can be used to treat rare forms of cancer.

It is recommended that scientific findings presented in a conference setting be considered preliminary until published in a peer-reviewed journal.