Progress in fighting cancer with the immune system tops this year's list of "breakthroughs" compiled by the leading journal Science.
Cancer immunotherapy is said to have undergone a "sea change" in 2013 as promising results emerged from a number of clinical trials.
The new therapies are designed to induce immune system cells into attacking and destroying tumours. Although their potential is yet to be fully realised, it could have a huge impact on cancer treatment in the future.
"This year there was no mistaking the immense promise of cancer immunotherapy," says Tim Appenzeller, Science journal's chief news editor.
"So far, this strategy of harnessing the immune system to attack tumours works only for some cancers and a few patients, so it's important not to overstate the immediate benefits. But many cancer specialists are convinced that they are seeing the birth of an important new paradigm for cancer treatment."
Many pharmaceutical companies that wanted nothing to do with cancer immunotherapy several years ago are now investing in the area heavily.
The nine other ground-breaking scientific achievements from the past year, in no order of rank, were as follows:
CRISPR: A gene-editing technique discovered in bacteria, and now used to carry out surgery on individual genes. This year, more than a dozen teams of researchers used it to manipulate the genomes of various plant, animal and human cells.
Perovskite Solar Cells: A new generation of solar-cell materials, cheaper and easier to produce than those in traditional silicon cells. Perovskite cells are not as efficient as commercial solar cells yet, but are improving fast.
Vaccine design based on structural biology: This year, scientists used the structure of an antibody to design an immunogen - the main ingredient of a vaccine - for a childhood virus that hospitalises millions each year. It was the first time structural biology had led to such a powerful tool for fighting disease.
CLARITY: An imaging technique which renders brain tissue transparent to make neurons visible. It changed the way scientists investigated the brain in 2013.
Mini-Organs: Scientists made remarkable progress growing miniature "organoids" in the laboratory. They included liver buds, mini-kidneys and tiny brains. Such miniaturised human organs may prove to be much better models of human disease than animals.
Cosmic rays from supernova remnants: Although discovered a century ago, scientists have not been sure where the high-energy particles from outer space known as cosmic rays come from. This year, they finally traced the rays to debris clouds left by supernovae, or exploding stars.
Human cloned embryos: Scientists were able to derive stem cells from cloned human embryos after finding that caffeine plays an important role in the process, stabilising key molecules in delicate human egg cells.
Why we sleep: Studies on mice showed how the brain flushes itself out with cerebrospinal fluid during sleep, getting rid of toxins such as the amyloid protein linked to Alzheimer's disease. The finding suggests that brain cleaning is one of the primary purposes of sleep.
Personal microbes and health: Research on the trillions of bacterial cells that call the human body home made it clear how much the bugs do for us. Personalised medicine will have to take these microbial tenants into account to be effective.
