Tiny gene fault causes rare form of ovarian tumour

In collaboration with the Press Association

Canadian scientists have identified a single genetic mistake that appears to cause a rare form of ovarian tumour called a granulosa cell tumour.

This rare form of tumour only occasionally becomes cancerous, and accounts for under five per cent of cases of ovarian cancer.

Researchers at the Ovarian Cancer Research (OvCaRe) Program at BC Cancer Agency and the agency's Genome Sciences Centre used a new DNA sequencing technology to study the genetic code of four granulosa cell tumour samples.

The main benefit of the new DNA sequencing technology is that it can decode billions of nucleotides at high speed - a feat that would have been impossible just a couple of years ago.

The team discovered a single mistake out of the three billion nucleotide pairs that made up the genetic code of the tumour samples.

This same mistake, which occurs in the FOXL2 gene, was found in each of the four tumour samples looked at by the team, indicating that the fault causes this rare type of ovarian cancer.

The team also confirmed their finding by examining nearly 100 additional granulosa cell tumour samples from around the world, revealing that the single fault occurs in almost all granulosa cell tumours and not in other types of cancer.

Dr David Huntsman, lead author and genetic pathologist at the British Columbia Cancer Agency and Vancouver General Hospital, said that the discovery "clearly shows the power of the new generation of DNA sequencing technologies to impact clinical medicine".

Dr Huntsman revealed: "Based upon our success in decoding granulosa cell tumours we are focusing on other rare tumours.

"We hope that these studies will not only help future patients with rare tumours but will also teach us about more common ones as well."

Dr Dianne Miller, an expert in gynaecologic cancers at the BC Cancer Agency and Vancouver General Hospital, noted that granulosa cell tumours are unique.

"Now that we have this pathway, we can look for existing cancer drugs that might work on this particular gene mutation" she added.

Commenting on the study, which appears in the New England Journal of Medicine, Dr Joanna Owens, Cancer Research UK's science information manager, said that gene sequencing technology is providing "amazing new insights" into many types of cancer.

"It's great to see this beginning to bear fruit for a rarer form of the disease," she said.

"The challenge now is to work out how to turn this new knowledge into drugs or diagnostics that can bring benefits to people with granulosa cell tumours."

References

Shah, S., Kobel, M., Senz, J., Morin, R., Clarke, B., Wiegand, K., Leung, G., Zayed, A., Mehl, E., Kalloger, S., Sun, M., Giuliany, R., Yorida, E., Jones, S., Varhol, R., Swenerton, K., Miller, D., Clement, P., Crane, C., Madore, J., Provencher, D., Leung, P., DeFazio, A., Khattra, J., Turashvili, G., Zhao, Y., Zeng, T., Glover, J., Vanderhyden, B., Zhao, C., Parkinson, C., Jimenez-Linan, M., Bowtell, D., Mes-Masson, A., Brenton, J., Aparicio, S., Boyd, N., Hirst, M., Gilks, C., Marra, M., & Huntsman, D. (2009). Mutation of FOXL2 in Granulosa-Cell Tumors of the Ovary New England Journal of Medicine DOI: 10.1056/NEJMoa0902542