Bowel cancer is four distinct diseases, each with a different prognosis, scientists have discovered.
Armed with this new knowledge, doctors might better determine which patients need the most aggressive treatment, the Institute of Cancer Research team say.
They looked at laboratory and clinical data from more than 3,000 patients with bowel cancer to see if they could better classify the disease.
Nearly all of the tumours could be sorted into the four groups.
The groups focus on the genes a tumour contains, rather than just the type of bowel tissue that it affects or how far it has spread - although those factors are important too.
Grouped by genes
Cancers that fit the four consensus molecular subtypes (CMS1, CMS2, CMS3 and CMS4) share genes that dictate their behaviour and might also make them more or less vulnerable to certain treatments, Nature Medicine reports.
Patients with CMS4 tend to have the worst prognosis and might need more extensive treatment, for example, while those with CMS2 have much better survival rates, even if the cancer returns.
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Researcher Dr Ganiraju Manyam said the discovery was important for knowing how best to treat patients.
"The next step is to match existing therapies with these groups so that we can begin to personalise treatment.
"Some of these patients might be undergoing chemotherapy when they do not need it and could be spared it."
Lucy Holmes, Cancer Research UK's science information manager, said: "Each patient's cancer is unique and we need to tailor treatments and move away from a 'one size fits all' approach. Studies like this showing different types of a certain cancer are helping us get there."
Ms Cafferkey, from Cambuslang in South Lanarkshire, spent almost a month in isolation at the beginning of the year after contracting the virus in December 2014.
Bodily tissues can harbour the Ebola infection months after the person appears to have fully recovered.
Toni Cafferkey told the Sunday Mail that her sister had gone to a GP out-of-hours clinic at the Victoria Hospital in Glasgow on Monday night but the doctor who assessed her diagnosed a virus and sent her home.
She said: "At that point me and my family believe they missed a big opportunity to give the right diagnosis and we feel she was let down. Instead of being taken into hospital, she spent the whole of Tuesday very ill.
"I think it is absolutely diabolical the way she has been treated... We don't know if the delays diagnosing Pauline have had an adverse effect on her health, but we intend to find out.
"It has not been good enough. We think there have been major failings and we just want her to pull through. This kind of recurrence seems to be rare but we don't yet know enough about it."
NHS Greater Glasgow and Clyde confirmed that Ms Cafferkey did attend the New Victoria Hospital GP out-of-hours service on Monday.
A spokesman said: "Her management and the clinical decisions taken based on the symptoms she was displaying at the time were entirely appropriate.
"All appropriate infection control procedures were carried out as part of this episode of care."
On Friday, a statement from the Royal Free Hospital confirmed Ms Cafferkey had been transferred to the hospital "due to an unusual late complication of her previous infection by the Ebola virus".
It added: "The Ebola virus can only be transmitted by direct contact with the blood or bodily fluids of an infected person while they are symptomatic, so the risk to the general public remains low and the NHS has well-established and practised infection control procedures in place."
Mr Cameron's comments came as the government denied pressuring officials behind the scenes to delay the publication of figures which show the financial performance of the NHS.
A report in the Observer claimed officials at Monitor and another NHS regulator were leaned on to delay financial and other performance figures such as treatment waiting times in order to avoid embarrassment at the Conservative conference, which is taking place this week.
Health officials have said the data will be published shortly.
'Clear goals'
On the BBC's Andrew Marr Show, Mr Cameron insisted a seven-day-a-week NHS was "a really exciting prospect".
He said: "We said that we are going to have to make difficult decisions elsewhere, but the NHS will not just be protected.
"It's getting an extra £10bn of money during this Parliament, over and above inflation, and that enables us to meet some really clear goals.
"Parents and people in our country want to access the NHS on a seven-day basis.
"Let me be clear, this doesn't mean that all staff in the NHS have to work every seven days, it just means the services are available.
"So, I can announce today that we will be publishing a new GP contract to get rid of the box-ticking and the form-filling."
The new contract for GPs will be voluntary, with family doctors able to decide whether they want to join forces with neighbouring GPs to form federations and networks of practices delivering seven-day care to populations of at least 30,000 patients.
Grouping GPs together in federations or networks will allow them to deliver better integrated care, the prime minister argues.
They will also be able to work more closely with community nurses, hospital specialists, pharmacists and other health and care professionals, he added.
Destabilising care
Trials of seven-day GP access have already begun, with 18 million patients getting extended availability by March this year.
But a recent survey found practices in some areas had scaled back weekend opening due to limited demand.
Conservative sources said the voluntary GPs contract will be funded from the additional £10bn of NHS investment promised by the prime minister over the course of the Parliament.
Labour's Jonathan Ashworth said: "You can't trust [David Cameron's] promises on a seven day NHS - he has made them before but hasn't delivered.
"What the Tories have done is take the health service backwards - under them it is harder to see your GP and waiting lists are higher."
Media captionSecretary of the Nobel Academy at Karolinska Institutet Urban Lendahl made the announcement
The mosquito-borne disease malaria kills more than 450,000 people each year around the world, with billions more at risk of catching the infection.
Parasitic worms affect a third of the world's population and cause a number of illnesses, including river blindness and lymphatic filariasis.
Deadly parasites
After decades of limited progress, the discovery of the two new drugs - ivermectin for river blindness and lymphatic filariasis, and artemisinin for malaria - was a game-changer.
Image copyrightCDC
Efforts to eradicate malaria had been failing - older drugs were losing their potency - and the disease was on the rise.
Prof Youyou Tu, who in the 1960s had recently graduated from the Pharmacy Department at Beijing Medical University, looked to traditional herbal medicine to find a potential therapy.
She took an extract from the plant called Artemisia annua, or sweet wormwood, and began testing it on malaria parasites.
The component, later called artemisinin, was highly effective at killing them.
Image copyrightReutersImage captionYouyou Tu is Chief Professor at the China Academy of Traditional Chinese Medicine
Today, the drug is used around the world in combination with other malaria medicines. In Africa alone, this is saving more than 100,000 lives every year.
Tu is the 13th woman to win this Nobel Prize.
She shares the award with two men who found a treatment for another parasite - roundworm.
Their research led to the development of a drug called ivermectin, which is so successful that roundworm diseases are on the verge of eradication.
Satoshi Ōmura, a Japanese microbiologist, focused on studying microbes in soil samples. He selected a number of promising candidates that he though might work as a weapon against diseases.
Irish-born William C Campbell, an expert in parasite biology working in the US, then explored these further and found one was remarkably efficient against parasites.
Image copyrightTrinity College DublinImage captionDr Campbell now works at Drew University in the US
The active ingredient, avermectin, went on to become a drug known as ivermectin which is now used to treat river blindness and lymphatic filariasis.
River blindness is an eye and skin disease that ultimately leads to blindness. Lymphatic filariasis, also known as elephantiasis, causes painful swelling of the limbs. Both affect people living in some of the poorest countries in the world.
'Out of the blue'
Dr Colin Sutherland, of the London School of Hygiene and Tropical Medicine, said it was immensely gratifying that the achievements in tackling these important diseases had been recognised.
"It's come out of the blue but we are very excited that the committee recognised the importance of parasitic diseases."
The Nobel committee said: "The two discoveries have provided humankind with powerful new means to combat these debilitating diseases that affect hundreds of millions of people annually.
Image copyrightReutersImage captionSatoshi Ōmura has discovered more than 470 compounds during his career as a scientist
"The consequences in terms of improved human health and reduced suffering are immeasurable.''
Omura told Japanese broadcaster NHK: "I have learned so much from microorganisms and I have depended on them, so I would much rather give the prize to microorganisms.
"This is kind of a low-profile research area, but microorganisms are extremely important for humans. They can be our partners. I hope the area gets more attention because of the prize so that it can further contribute to human beings."
Previous winners of the Nobel Prize for physiology or medicine
Image copyrightSCOTT CAMAZINE/SCIENCE PHOTO LIBRARYImage captionLast year's winners helped us to understand the brain's orienting 'GPS'
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