N. Engl. J. Med. doi:0.1056/NEJMoa1008433 (2010); Science doi:10.1126/science.1196333 (2010)

Genome sequencing has revealed two genes involved in a deadly form of ovarian cancer.

Ovarian clear-cell carcinoma is aggressive and difficult to treat. David Huntsman at the British Columbia Cancer Agency in Vancouver, Canada, and his colleagues sequenced protein-coding genes from 18 ovarian clear-cell tumours and found that six had mutations in a gene called ARID1A. The ARID1A protein regulates the coiling of DNA and hence gene expression, and has also been linked to tumour suppression.

Meanwhile, a team led by Kenneth Kinzler, Victor Velculescu and Nickolas Papadopoulos of the Johns Hopkins Kimmel Cancer Center in Baltimore, Maryland, sequenced protein-coding genes in eight tumours and uncovered mutations in ARID1A and another gene called PPP2R1A. The PPP2R1A protein helps to distribute chromosomes into dividing cells and controls cell growth. A follow-up experiment with 42 tumours showed that 57% had mutations in ARID1A and 7% had mutations in PPP2R1A.