What Causes BPH? - Prostate Cancer Foundation

The quick answer is, we don't know. Like wrinkles and gray hair, BPH just seems to come with the territory of aging. For reasons that are not clear, beginning at around age forty—in some men more than others—the inner zone of the prostate begins to grow. But even this is more complicated than it sounds. BPH involves two different kinds of tissue: glandular, made up of epithelial cells (the glandular factories that make the prostate's secretions) and smooth muscle cells (which contract to squeeze the secretions into the urethra). Somehow, BPH sets these two types of tissue at odds: it's the epithelial tissue that makes the lumpy lobes, but the smooth muscle tissue reacts to this buildup by tightening around the urethra.

Scientists suspect that the aging prostate somehow becomes more sensitive to testosterone, even though there's less of it floating around in the bloodstream. Why? As men age, testosterone production starts to fall—but the body's levels of estrogen (which normally are very low in men) remain about the same. We know that even a slight amount of estrogen can make testosterone more powerful; it may be that this imbalance in androgen and estrogen levels contributes to the disease. Also, the tissue changes in BPH may be triggered by substances called growth factors, possibly those made by muscle cells in the prostate.

Curiously, even though the tissue is growing—which normally would mean a big increase in the number of cells being made—the enlarging prostate makes about the same number of cells as always. How can this be? In any tissue, there is a finely tuned balance between the number of new cells and the number of cells that are dying. Apparently, the population boom in BPH isn't due to an increase in cell birth but to a decrease in cell death. For some reason, the cells in BPH are living much longer. Some process—perhaps an increase in growth factors—has altered their normal life span, creating a "fountain of youth" for prostate cells. Although the growth is not malignant, the process is similar to what's happening in prostate cancer—which suggests that, once we understand the factors that control cell death in BPH, we may have a better approach for controlling it in cancer as well.

BPH: New Markers and New Questions

BPH doesn't just affect the prostate and, although it isn’' cancer, it isn't always benign. It affects the bladder, and in severe form, its symptoms can be debilitating. "Until recently, all BPH was considered to be a single disease," notes Robert Getzenberg, Director of Research at the Brady Urological Institute at Johns Hopkins. But his research group has found a genetic marker called JM-27 that's associated with the most aggressive type of BPH. Further, Getzenberg and colleagues have developed a blood test that can determine whether a man has the most severe form of BPH or whether his case is mild. They hope that this test will even be able to predict how a man will respond to various treatments of BPH. "This is the first BPH-specific marker that has been identified, and we hope it will play a role in how men are treated for the disease," he says.

BPH and prostate cancer affect different regions of the prostate, but they're both associated with aging. They may have other things in common as well, says Getzenberg. "We have identified a series of genes that appear to be altered in both BPH and prostate cancer. There may be much more connection between BPH and prostate cancer than we originally envisioned. Understanding more about the development of each of these diseases will help us develop better tools with which to attack them both."