islamabad - Sleeping immune cells which are already in tumours can be `woken up’ to fight even the most deadly cancers, scientists have discovered.

In order to evade the body’s defence mechanism, cancer cells have learned to flick a switch in immune cells which switches them off. The switch is there to stop the body wrongly attacking harmless invaders, and is the reason that a mother can carry a baby essentially a foreign body without the immune system attacking the foetus.

Now scientists at Cancer Research UK and University College London have proven it is possible to use genetic editing to snip away the `off switch’ so that the immune system recognises cancer again. Researchers say it is like `cutting the brakes’ and allowing immune cells to do the rest. Dr Sergio Quezada, Cancer Research UK scientist and co-lead author from

University College London’s Cancer Institute, said: “This is an exciting discovery and means we may have a way to get around cancer’s defences while only targeting the immune cells that recognise the cancer.”

The treatment would work by taking a biopsy of a tumour and then identify immune cells that are already inside. Those cells are likely to me most effective as the fact that they are in the tumour suggests they were trying to attack it before they got switched off.

Scientists then use a genetic editing technique called Talen to remove the `off switch’. The edited immune cells are then multiplied in a lab and replaced back in the body. Not only will the new cells fight cancer but they should prevent it from returning. So far tests have only been carried out on mice, but tumours shrunk by 75 per cent, and 80 per cent of the disease mice were still alive after 70 days compared with non from the control group.

Dr Alan Worsley, Senior Science Communications Office at Cancer Research UK added: “I think this is quite exciting. We are essentially cutting the brakes. It’s very simple and elegant and could really help patients who have tried everything else and nothing has worked. “With chemotherapy it only keeps working until the drugs stop, but this will just keep going.” Drugs which target the `off switch’ in immune cells are already available, but they can have debilitating side-effects and can send the immune system into overdrive. leading to it attacking healthy cells.

Professor Peter Johnson, Cancer Research UK’s chief clinician said: “We know that some cancers can switch off the cells of our immune system, and this interesting laboratory research suggests a new way that we might be able to get around the problem, although this is still some way away from use in the clinic.”

Why your brain could be making you fat

Overweight people react very differently to real food and inedible images of snacks displayed on a computer screen, a study has found. In tests, both overweight and lean volunteers made similar decisions when given food choices in the form of images.

But it was another story when they were offered an all-you-can-eat buffet of real food including sandwiches, desserts, and drinks.

The new study found overweight people make diet choices divorced from their knowledge about healthy food. While lean and overweight participants were equally attracted to foods rated as tasty, the latter were more likely to go for the unhealthy, fattening items.

Lead researcher Dr Nenad Medic, from Cambridge University, said: ‘There’s a clear difference between hypothetical food choices that overweight people make and the food they actually eat.’

Even though they know that some foods are less healthy than others and say they wouldn’t necessarily choose them, when they are faced with the foods, it’s a different matter.

‘This is an important insight for health campaigners as it suggests that just trying to educate people about the healthiness of food choices is not enough. The presence of unhealthy food options is likely to override people’s decisions.

‘In this respect, food choice does not appear to be a rational decision - it can become divorced from what the person knows and values.’

For the study - which was published in the journal eNeuro - the researchers recruited 23 lean and 40 overweight individuals, who were first asked to rate 50 common snack foods presented on a computer screen.

Researchers at Cambridge University analysed 60 people on their diet and found that real-life temptation trumped a person’s will-power more often if they were fat  

Dr Nenad Medic, who authored the bstudy, claims this an important insight for health campaigners as it suggests educating people about good food choices is not enough

They were told to score each item on a five-point scale for healthiness and tastiness.

Every participant was then asked to swap a “neutral” food item for another food item from the list of images.

Body weight had no bearing on the decisions made during this task, and scans showed no difference in brain activity between lean and overweight volunteers.

In the ‘buffet’ experiment, the healthy food items were paired with unhealthy alternatives. For instance, one choice was between a “healthy” chicken or “unhealthy” BLT (bacon, lettuce and tomato) sandwich.

Overweight participants consumed comparably more unhealthy foods than lean participants. As well as being overweight, impulsivity was associated with unhealthy food choices from the buffet. The more impulsive participants were, the more they were likely to pick the unhealthy items.