Skin cancer continues to be the most common cancer in the United States. Each year over one million cases are reported, representing about one out of every three new cancer diagnoses in this country, and this rate has increased over the last decade. All this is despite the common knowledge that many cases of skin cancer are preventable.
Exposure of unprotected skin to the ultraviolet (UV) radiation of the Sun dramatically increases the risk of developing skin cancer because UV rays can damage skin cells' DNA. Even one or two bad sunburns over a lifetime can be enough to cause skin cancer.
The increased rate of skin cancer over the last several years is partly attributable to cultural trends: Skimpy bathing suits and an obsession with tanned skin lead many Americans, particularly younger ones, to spend much of the summer months baking with little protection.
Environmental changes have also affected the incidence of skin cancer. Depletion of the ozone layer, which reached its worst levels ever during the 1990s and has only slowly recovered since, allows more UV radiation to reach the Earth's surface.
These statistics motivate an urgent need to study the causes, prevention and treatment of various forms of skin cancer. Recently a group of researchers at the Hopkins Bloomberg School of Public Health studied an interesting method of preventing the disease: broccoli.
Broccoli contains large amounts of a chemical called sulforaphane which has both anti-cancer and antibiotic activity in human cells. Sulforaphane, which was discovered by Hopkins researchers, is produced by the breakdown of another chemical, glucoraphanin, in damaged plant cells.
Sulforaphane is thought to help block the effects of UV radiation in cells. It is also found in high concentrations in brussel sprouts, cauliflower and cabbage, particularly in young vegetables and sprouts.
The researchers produced a broccoli sprout extract with a high concentration of sulforaphane and applied it topically, or directly on the skin, in both mice and humans. This is obviously similar to the application of sunblock, so it is a practical way to promote its use.
The results were astounding.
The mice demonstrated several signs of protection against UV rays, showing decreased signatures of skin damage and lower rates of skin cancer over time.
In humans, the protective effects were not only significant but long-lasting after only one application. Potentially, sulforaphane could be administered infrequently.
Despite these results, it is far too early to recommend the routine use of sulforaphane or broccoli sprout extract for general consumers. More tests will be needed to clarify the chemical's mechanism and benefits.
If this research pans out, however, the results could be significant. An effective anti-cancer agent produced by a cheap, renewable plant could be widely useful.
