Anyone who has been through - or seen at close hand - the effects of cancer treatment knows how devastating it can be. For those scientists working to improve patients' experience of the treatment that could save their life, gene therapy is one of the great hopes. Researchers have now identified a group of 87 genes that may determine how well cancer patients respond to chemotherapy.

Scientists hope manipulating the genes could open the door to more effective and personalised treatments.

The researchers screened more than 20,000 human genes for biological activity. They found 87 that seemed to affect the sensitivity of cancer cells to chemotherapy drugs.

Blocking the action of some of them made lung cancer cells 10,000 times more sensitive to the drug Paclitaxel. Less dramatic effects were seen with the chemotherapy drugs Vonorelbine and Gemcitabine.

The results raise the possibility of lowering chemotherapy doses and reducing the side-effects of drugs without compromising their effectiveness.

Professor Michael White, of the University of Texas Southwestern in the US, who led the research, says: "Chemotherapy is a very blunt instrument. It makes people sick, and its effects are very inconsistent.

Identifying genes that make chemotherapy drugs more potent at lower doses is a first step toward alleviating these effects in patients."

The study, published today in the journal Nature, looked only at isolated cells in the lab. Further research will be needed to determine whether blocking the genes in living animals has the same effect.

The red, red grass of alien homes
Green fingers may not do gardeners much good on Earth-like worlds outside the solar system. Scientists predict that alien vegetation may be mainly yellow, orange or red rather than green.

Nature's colour scheme depends chiefly on the type of star a planet orbits and the components of its atmosphere. Researchers in California carried out computer simulations to see what plants on other planets might be like.

Chief scientist Dr Nancy Kiang, from the US space agency Nasa's Goddard Institute for Space Studies, says: "The dominant colour of photosynthesis could be yellow or orange or maybe r ed. I think it is unlikely that anything will be blue."

Foliage colour is determined by the wavelengths of light absorbed by plants to drive photosynthesis, the mechanism they use to produce sugar. The light reaching a planet's surface varies according to the radiation emitted by the parent star and the filtering effect of atmospheric gases.

On Earth, chlorophyll in plants absorbs blue light because it is energetic, and red light, which is plentiful. Terrestrial vegetation can get all the energy it needs from blue and red wavelengths in sunlight. Earth plants can do without light in the green part of the spectrum, which is reflected away. As a result, green dominates the natural landscape on Earth. But on other planets, where the colour mix of light is different, it may be better for plants to absorb green wavelengths and reflect red or yellow.

The research, conducted at the California Institute of Technology, is published today in the journal Astrobiology.