Washington, Jan 4 : An experimental drug undergoing tests against breast and lung cancer shows promise in fighting brain cancer (glioblastoma) and prostate cancer too, says a new research.

The drugs are especially encouraging because they attack not only the bulk of the tumour cells but also the rare cancer stem cells that are believed to be responsible for cancer's growth, said study author Jerry Shay, professor of cell biology.

"Because it attacks a mechanism that's active in most cancers, it might prove to be widely useful, especially when combined with other therapies," said Shay at the University of Texas Southwestern Medical Centre (UTSMC).

The drug's actions, observed in two pre-clinical studies, isolated human cells in one trial and in rodents in the other.

In the glioblastoma study, performed in mice, the drug also crossed from the bloodstream into the brain, which is especially important because many drugs are not able to cross the blood-brain barrier.

Glioblastomas are the most common malignant brain tumours in adults. They are difficult to treat with drugs because blood vessels in the brain have tightly constructed walls that allow only a few substances to pass through, says a release of UTSMC.

The study appears in the January issue of Clinical Cancer Research. The prostate cancer study is available online in the International Journal of Cancer.(IANS)