The Nobel Prize in Chemistry for 2015 has been awarded to three scientists whose work is adding add immensely to the understanding of human cells.

Members of the judging panel awarded the prize jointly to Tomas Lindahl, Paul Modrich and Aziz Sancar for having mapped, at a molecular level, how cells repair damaged DNA and safeguard genetic information. Their work has provided fundamental knowledge of how a living cell functions and is already being used for the development of new cancer treatments. Tomas Lindahl works at the Francis Crick Institute and Clare Hall Laboratory, Hertfordshire, UK, Paul Modrich at the Howard Hughes Medical Institute and Duke University School of Medicine, Durham, NC, USA, and Aziz Sancar, at the University of North Carolina, Chapel Hill, NC, USA. All three have carried out work which examined the nature of changes in human cells and their relationships to diseases such as cancer. Each day our DNA is damaged by UV radiation, free radicals and other carcinogenic substances, but even without such external attacks, a DNA molecule is inherently unstable.

Thousands of spontaneous changes to a cell’s genome occur on a daily basis and defects can also arise when DNA is copied during cell division, a process that occurs several million times every day in the human body. The reason our genetic material does not disintegrate into complete chemical chaos is that a host of molecular systems continuously monitor and repair DNA. The Nobel Prize in Chemistry 2015 awards three pioneering scientists who have mapped how several of these repair systems function at a detailed molecular level. Tomas Lindahl demonstrated that DNA decays at a rate that ought to have made the development of life on Earth impossible. This insight led him to discover a molecular machinery, base excision repair, which constantly counteracts the collapse of our DNA. Aziz Sancar has mapped nucleotide excision repair, the mechanism that cells use to repair UV damage to DNA.

People born with defects in this repair system will develop skin cancer if they are exposed to sunlight. The cell also utilises nucleotide excision repair to correct defects caused by mutagenic substances, among other things Paul Modrich has demonstrated how the cell corrects errors that occur when DNA is replicated during cell division. This mechanism, mismatch repair, reduces the error frequency during DNA replication by about a thousandfold. Congenital defects in mismatch repair are known, for example, to cause a hereditary variant of colon cancer. According to the judging panel from Royal Swedish Academy of Sciences, the Nobel Laureates in Chemistry 2015 have provided fundamental insights into how cells function, knowledge that can be used, for instance, in the development of new cancer treatments.

Tomas Lindahl was born 1938 in Stockholm, Sweden and was Professor of Medical and Physiological Chemistry at University of Gothenburg between 1978–82 before becoming Emeritus group leader at Francis Crick Institute and Emeritus director of Cancer Research UK.

American Paul Modrich is an Investigator at Howard Hughes Medical Institute and James B. Duke Professor of Biochemistry at Duke University School of Medicine, Durham, NC, USA.

Aziz Sancar, a US and Turkish citizen, is Sarah Graham Kenan Professor of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, USA.