14 DAY TRIAL // Bladder cancer turns into a nightmare the life of its victims, triggering excruciating piss problems. The disease affects about three times as many men as women: 50,000 men are estimated to develop it this year compared to 17,000 women in the US.
Now a team led by Dr Chawnshang Chang, of the University of Rochester Medical Center can explain why: this cancer development appears to be determined by the testosterone molecular receptor protein, which is much more active in men than women.
Mice with the receptor removed displayed dramatically lower percentages of bladder cancer than normal mice, and human cancer cells with the receptor intact were much more active than those lacking it. Mice get bladder cancer for the same reasons as women.
"Some scientists have suspected that male hormones working in concert with the androgen receptor might play a role, but hard evidence has been minimal until now," said co-author Dr. Edward Messing, a bladder cancer expert and Chair of Urology.
Rather hard smoking and industrial chemicals have been blamed till now. "More and more women are smoking and working with chemicals in the workplace, yet their bladder cancer rates have not really changed much. There is no longer any question that the androgen receptor is playing a role in bladder cancer." said Messing.
Androgen receptor triggers many other diseases and conditions, most known being the prostate cancer. Perhaps chemicals used against prostate cancer could work with bladder cancer.
Normal mice exposed to cancer-inducing chemicals got high levels of bladder cancer: 92 % of the males and 42 % of the females, while in the case of engineered mice lacking the protein not a single individual developed bladder cancer, and they also displayed much less premalignant changes in their bladder.
"The findings could help doctors decide which cases of bladder cancer are most likely to re-occur." said Chang.
Cancer tumors were more likely to re-appear if the receptor protein was more abundant.
Some of those mice lacking the receptor received DHT, a male hormone drug. 25 % of these mice got bladder cancer, thus the hormone can elude receptor pathway to inflict an effect.
Simply cutting off the testosterone supply will have only a limited effect. Other researches revealed that even estrogen (female sex hormone) can activate the androgen receptor.
"The activity of the androgen receptor is different from the activity of hormones that target the receptor. We've shown very clearly that even without these hormones, the receptor is still active in the development of cancer. This is crucial information as doctors seek to develop treatments for diseases like prostate or bladder cancer in men." said Chang.