Prostate cancer is the second deadliest cancer in men. One in six will be diagnosed with prostate cancer during his lifetime. Though treatments are more effective than ever, some patients reach a point when their cancer no longer responds to chemotherapy. Now, researchers have found a way to switch the chemo back on for these patients, and improve their chances.

When Paul Roundy was diagnosed with prostate cancer five years ago, he approached it with the same determination that made him successful in business.

"Yes, I was very optimistic, although, I was pretty much aware that prostate cancer does have a life of its own," said Roundy.

After surgery and years of treatment, Roundy's chemo stopped working.

"The problem with chemo is that many patients do not respond to chemotherapy in the first place, and the patients that do respond stop responding after certain duration of treatment," said Dr. Rakesh Singal, medical oncologist at the University of Miami Sylvester Cancer Center in Florida.

Singal discovered a gene necessary for chemotherapy to work. It's often shut off in cancer cells. He's testing a drug that would trick the cancer cells into responding to chemo. In trials, patients get the drug called Vidaza daily for five days before chemo.

"So this drug turns the gene on and the chemotherapy starts working again," said Singal.

So far, Roundy's PSA, a measure for prostate cancer, dropped from about 30 to three.

"You can't feel it in your body, but you can see the results and see the numbers as they come out every three weeks as the PSA continues to lower," said Roundy.

Clinical trials of this gene activation therapy for prostate cancer are continuing at the Sylvester Cancer Center. Researchers say the same kind of treatment could one day be used to treat other kinds of cancer that have become resistant to traditional drug therapy.

BACKGROUND: Prostate cancer is the most common cancer in American men, following skin cancer. According to the American Cancer Society, about 192,280 new cases of prostate cancer will be diagnosed each year, and prostate cancer accounts for about 10 percent of cancer-related deaths in men. One in six men will be diagnosed with prostate cancer during his lifetime. Prostate cancer starts in the prostate gland, part of the male reproductive system.

CHEMOTHERAPY RESISTANCE: Treatment options for prostate cancer vary based on the stage of the cancerous tumor. Prostate cancer that has spread or that is resistant to hormonal treatments may be treated with chemotherapy.

In some cases, the cancer may become resistant to chemotherapy. This occurs when a cancer that had been responding to therapy begins to grow again. This may be due to a mutation of the cancer cells, cancer cells repairing the DNA breaks caused by the chemotherapeutic drugs, or cancer cells developing a means to inactivate the drugs. In an attempt to prevent drug resistance, clinicians often give chemotherapy drugs in combination. This is meant to reduce the likelihood of developing a resistance to any single drug.

A new approach to combating chemotherapy resistance in prostate cancer patients is in clinical trials at the University of Miami. Researchers discovered a gene that appears to be responsible for activating chemotherapy in prostate cancer cells. Sometimes, this gene gets turned off, and thus chemotherapy stops working.

"What we found is another way of activating the gene again," said Singal.

Singal and his team give a drug called Vidaza for several days prior to administering chemotherapy. The drug works by preventing the gene responsible for chemo activation from turning off.

"Right now, there are no good options for patients who stop responding to (chemotherapy) … but now there seems to be an option," said Singal.