Breast Cancer Drug Seems to Work on Mesothelioma, Too

Don’t feel it’s an insult to your manhood if your oncologist says he wants to treat your mesothelioma by putting you on the same drug some women take for breast cancer.

That medication might turn out be your best shot at stopping mesothelioma from metastasizing.

The drug is exemestane. Researchers from Italy’s Regina Elena National Cancer Institute recently discovered that exemestane puts the brakes on mesothelioma when given to male lab mice.

The researchers report that mesothelioma growth is blocked by exemestane through a process that ratchets down the cancer’s ability to express certain genes. The genes are cAMP, pCREB and CD44.

Squelching that last one — CD44 — is particularly important because it supports the ability of mesothelioma cells to uproot and move to other parts of the body, the researchers indicate.

According to the researchers, giving the test mice exemestane caused a “significant reduction of [mesothelioma] cell proliferation, survival, [and] migration ….”

Writing in the March issue of Molecular Cancer, the researchers added that exemestane also caused a significant decrease in tumor size.

Moreover, the researchers found that combining exemestane with the chemotherapy drug pemetrexed gets better results than does the conventional cocktail of pemetrexed mixed with cisplatin.

Estrogen Fuels Cancer Growth

Certain breast cancers need estrogen to grow. The cellular mechanism that allows breast cancer to feed on estrogen is an enzyme called aromatase.

Exemestane interferes with the ability of aromatase to synthesize estrogen into something that cancer cells can consume for nourishment.

Unable to take in the estrogen they need, the cancer cells go hungry and malfunction. Eventually, they stop replicating. In the best case scenario, they starve to death.

Until a few years ago, it was thought that estrogen was a hormone exclusive to women. But, as The New York Times reported in 2013, estrogen is in men, too.

According to The Times, male estrogen comes from naturally converted testosterone.

The problem for men as they grow old is that their bodies produce at least double the amount of estrogen as does a woman of the same age.

Unfortunately, as the Molecular Cancer article demonstrates, mesothelioma craves estrogen – and men are more than capable of giving the cancer what it wants.

So it comes as encouraging news to find that exemestane works in male mice to inhibit conversion of estrogen into a form that mesothelioma can use.

Looking Ahead to Testing

Human testing is the next order of business, and that is just what the researchers hope will be on tap.

Looking ahead to that next phase, researchers recognize that exemestane use by women does carry with it some risk of side effects. One is joint pain and decreased bone density, according to the University of New Mexico Cancer Center.

Some of those bone-density woes turn up in the lower back and hips. That’s troubling because a fall to the floor could mean months of recuperation in a hospital – which itself entails risks.

The extent to which such side effects will affect men who take exemestane won’t be known until clinical trials are completed.

But assuming the side effects are no worse for men, then exemestane could become an added important weapon in the ongoing war against mesothelioma.