Arlin Rogers Photo: Kelvin Ma

Warding off Liver Cancer

Worldwide, liver cancer is the second leading cause of cancer deaths after lung cancer, according to the World Health Organization. It’s particularly prevalent in Southeast Asia and sub-Saharan Africa, where it is associated with hepatitis B and C viruses, as well as toxins in food and water. Liver cancer is also far more common in males, who get it twice to eight times as often as females, depending on the country. This peculiarity has led Arlin Rogers, head of pathology at Cummings School of Veterinary Medicine, to discover a promising route to staving off the disease.

When Rogers and his colleagues tested pituitary hormones on liver cells, growth hormone showed little effect. Prolactin, however, reduced inflammatory responses markedly. Rogers surmised that prolactin may play a role in protecting women against liver cancer. He ran experiments with mice, including both females and males that could not produce prolactin. The female mice without the prolactin gene developed cancer at dramatically higher rates than those with the gene. There was even a mild effect in the male mice: those with prolactin got cancer at around the same rates as those without, but exhibited only a third of the tumors.

That finding holds promise for human patients. Drugs that raise prolactin levels—used mostly for treating psychiatric or gastrointestinal disorders—have already received FDA approval. Rogers tested one such drug in mice exposed to a chemical that induces liver cancer. Only twenty-two percent of male mice taking the drug contracted cancer, compared with a hundred percent of those not taking the drug.

Rogers published his findings in the Proceedings of the National Academy of Sciences last summer. He’s now working with statisticians at Tufts Medical Center to see if patients already taking these drugs are less prone to liver cancer. “We don’t think this is going to cure liver cancer,” Rogers says, “but it might help prevent it.”

MICHAEL BLANDING is a Boston-based freelance writer and author of The Map Thief.