Tumour barcode spells hope for better cancer diagnosis

CANCER patients could face improved diagnoses and survival rates with the development of a tumour barcode.

Researchers at Melbourne's Peter MacCallum Cancer Institute are building a genetic database of tumour tissue to help with the identification of primary cancers.

The database will use microarray technology to scan biopsied tissue from cancer patients in whom the primary disease location cannot be determined.

The head of the Peter MacCallum's microarray facility, Dr Andrew Holloway, said unknown primary tumours accounted for up to five per cent of new cancer diagnoses.

Holloway said current diagnostic techniques, involving time-consuming and costly testing, could identify about 40 per cent of these.

"The remaining 60 per cent are given generic chemotherapy and for them the prognosis is worst,'' he said.

"If a person has an unknown cancer, they won't survive much more than a year.

"But if you can identify the primary cancer in a patient, then you can convert it from an unknown primary to a high grade specific cancer and normally the survival will be better because they can have tissue specific chemotherapy."

While the research is preliminary, Holloway said results so far had been promising.

The group has positively identified about half of the seven unidentified tumour samples run through the array technology so far.

Holloway said that by building up the database to contain as many as 400 tumour tissue samples in the coming year, he expected the to achieve a success rate of 70 to 90 per cent.

"Tumours tend to hang on to their DNA profile like a fingerprint," he said.

"What we want to do is get these known tumours together and use them as a sort of barcode to identify the primary sources of cancers."

The project has been running for 18 months, with the database expected to be completed in a further 12 months and clinical trials to follow.

Holloway said few groups worldwide were doing similar work, with the Melbourne researchers' access to microarray technology and tumour samples providing a competitive advantage.

The group currently has ethics approval to collect samples from the Peter MacCallum and St Vincent's Hospital, with further proposals lodged with unnamed hospitals in Sydney and Perth.

In preliminary experiments completed this month, the researchers received unlabelled tumour samples from hospital tissue banks.

By putting the samples through the microarray process, the group found tumours were cross-matching with database samples, enabling the researchers to identify the primary cancer in 50 per cent of cases.

Holloway said that while the technology was unlikely to immediately replace existing diagnostic techniques, it could be used in cases where pathology was unable to identify a tumour.