Source of Invasive Bladder Cancers Identified

A single type of cancer stem cell has been identified as the source of most aggressive and invasive bladder cancers, according to a new study.

The study, published in the peer-reviewed scientific journal Nature Cell Biology, details how researchers associated with the Stanford University School of Medicine identified a single type of cell in the lining of the bladder that causes invasive bladder cancer.

According to the authors of the study, invasive bladder cancer affect more than 375,000 people across the world each year. The cancer, which spreads to replace the entire limning of the bladder, is largely untreatable.

Philip Beach, PhD, a co-authors of the study, said in a press release that the cancer is so difficult to treat because cancer cells practically root themselves in the bladder lining even before actually causing harm to a patient.

 "All of these cells have already taken several steps along the path to becoming an aggressive tumor," the researcher explained. "Thus, even when invasive carcinomas are successfully removed through surgery, this corrupted lining remains in place and has a high probability of progression."

So how does one treat it? Like with any invasive infection, physicians have to essentially kill it at the source. In this case, researcher looked for the source by exposing lab mice to a known carcinogen called N-butyl-N-4-hydroxybutyl nitrosamine(BBN). The BBN was regularly placed in the mice's drinking water and the animal's were then observed over a period of months. After six months, all mice had developed invasive bladder cancer.

The researcher then repeated this experiment using a fluorescent marking agent to help identify the spread of cancer from suspected sources. In the most successful of experiments, adult stem cells in the bladder lining that expressed a signaling protein strangely known as "sonic hedgehog" or SHH were identified with the marking agent, highlighting cells that arose from these stem cells. Researcher found that after exposing the mice to BBN, the resulting cancer cells in the bladder all appeared to be highlighted switch the marking agent, indicating that they originated from the SHH-expressing cells.

This is exciting news for researchers because knowing the cancer's source can help scientists develop new ways to try and fight what was once thought to be a largely untreatable form of cancer.

The study was published in Nature Cell Biology on April 20.