Hadassah discovers mechanism contributing to cancer in overweight women

Earlier studies have found that several types of cancer are directly affected by obesity, including breast cancer, which is dependent on the hormone estrogen in postmenopausal women.

 Dividing cancer cell (photo credit: INGIMAGE)
Dividing cancer cell
(photo credit: INGIMAGE)

Hadassah-University Medical Center researchers said they have found the mechanism that contributes to the aggressive progression of breast cancer in overweight women.

“In the new study, we were able to characterize one of the mechanisms of increased progression of breast cancer in overweight patients – a growing phenomenon in Western countries,” said Prof. Tamar Peretz, who was the clinician involved in the study led by Prof. Michael Elkin.

The study was published in the peer-reviewed Cancer Research journal. Elkin recently received a grant from the Israel Cancer Research Fund to continue this research.

Specifically, the researchers were able to demonstrate the role of the enzyme called heparanase and its effect on cancer in overweight patients.

Heparanase is a unique enzyme that was previously characterized and cloned by Prof. Israel Vlodavsky at Hadassah. This enzyme, Peretz explained, plays a central role in the ability of cancer cells to penetrate blood vessels, thus contributing to the progression of the cancer process through the development of metastases.

THE HADASSAH-UNIVERSITY Medical Center campus is seen in Ein Kerem. (credit: MOSHE SHAI/FLASH90)THE HADASSAH-UNIVERSITY Medical Center campus is seen in Ein Kerem. (credit: MOSHE SHAI/FLASH90)

“We wanted to understand the mechanism by which the link between obesity and cancerous growth exists and what its exact effect is,” she said.

According to Peretz, earlier studies have found that several types of cancer are directly affected by obesity, including breast cancer, which is dependent on the hormone estrogen in post-menopausal women. She said that cancer manifests itself more aggressively and treatments are often less effective in overweight patients diagnosed with estrogen-dependent breast cancer.

The team used obese mice to do their study, dividing them into two groups. One group had the presence of the enzyme heparanase, and the other didn’t. What they found was that when they deleted the ability of the heparanase to act, the mice were no longer resistant to therapy.

“The unequivocal finding was that in a mouse lacking the enzyme heparanase, obesity had no effect at all on tumor development,” Peretz said.

Next, she said, the goal would be to develop customized treatments for patients based on knowledge of this mechanism.