High-fat diet may fuel the spread of prostate cancer

Obesity is linked to prostate cancer, scientists know, but it’s not clear why. On Monday, researchers reported a surprising connection.

When prostate cancers lose a particular gene, they become tiny fat factories, a team at Beth Israel Deaconess Medical Center in Boston reported in a paper published in Nature Genetics.

Then the cancers spread from the prostate, often with deadly effect. Prostate cancers that have not lost that gene also can spread, or metastasize — in mice, at least — but only if they have a ready source of fat from the diet.

That finding suggests that dietary fat can substitute for the loss of the gene, fueling prostate cancer. Moreover, the investigators found, an obesity drug that blocks fat production can make metastatic prostate cancers regress in mice and prevent them from spreading. “What this paper suggests is that fat or high-fat diets promote more aggressive prostate cancer,”

The American Cancer Society estimates that prostate cancer will be diagnosed in about 165,000 American men this year, making it the second most common cancer in American men, behind only skin cancer.

Geneticists knew prostate cancers often start when a protective gene, PTEN, shuts down. But the tumors in men that lose only PTEN tend to languish, rarely spreading beyond the prostate and rarely becoming lethal. The cancers change, though, if a second gene, called PML, also shuts down. Suddenly, indolent cells become cancers that spread and kill. But why?

In the new study, researchers found that when PML was lost, cancerous cells — in petri dishes and in mice — started churning out fat, which may protect the cells from certain toxic molecules. But the fat also may help the cancers spread, the researchers suggested. PML is also lost in human metastatic prostate cancer, but it has never been clear what the consequences might be.

Then the group asked a bigger question: Could they could protect mice from metastatic cancer by blocking fat production? That led to the experiment with a new obesity drug, fatostatin. It not only halted the cancer’s spread in the animals, but made it regress. The Beth Israel Cancer Center group is planning a clinical trial with fatostatin to treat prostate cancer in humans.

Source NYT. More in the link

https://www.nytimes.com/2018/01/16/health/fat-diet-prostate-cancer.html