Cancer clues US researchers have found a way to visually track the spread of cancer cells. They can make them light up with a new imaging compound then monitor their movements with a tiny camera called an endoscope. The US National Cancer Institute team successfully tracked breast and ovarian cancers in mice and says the technique may enable doctors to monitor how well patients respond to therapy, Reuters reports. 'Our design concept is very versatile and can be used to detect many types of cancer,' says research team leader Hisataka Kobayashi. No more jet lag? An experimental drug that acts like the body-rhythm hormone melatonin appears to help overcome sleep disruption and may prove useful against jetlag. Harvard University researchers report initial success when used on people whose sleep schedule was suddenly altered by five hours. Those given tasimelteon, rather than a placebo, slept significantly longer and said they slept better, WebMD reports. You're only as old as you feel An ongoing six-year study of more than 500 people older than 70 by University of Michigan researchers has found that they feel, on average, 13 years younger than they are. However, the gap between how young the participants say they feel and their actual age generally narrows as they age. At the start of the study, men typically were more satisfied about their ageing than women, but this deteriorated faster over the six years, AFP reports. Out-of-body experience Swedish neuroscientists have managed to make people think someone else's body was their own, in a series of studies that may be useful in developing virtual-reality applications and robot technology. 'In one of the experiments, subjects 'swapped' bodies with other people and shook hands with themselves without the illusion being broken,' say the Karolinska Institute researchers. The studies entailed changing the brain's perception of itself by using cameras to show people what someone else could see, AFP reports. Cocaine low Spain, which has the highest rate of cocaine use in Europe, will test a vaccine next year that blocks the drug's high. The initial trials will involve more than 160 people. Last year, about 22,000 Spaniards sought treatment for cocaine addiction. The vaccine doesn't eliminate cravings, AFP reports. Instead, the idea is that, when patients don't get their usual enjoyment from the drug, they 'become frustrated that they spent their money for nothing', says psychiatrist Carlos Alvarz Vara.