Researchers at the BC Cancer Agency have produced a new technology that may revolutionize our ability to identify genetic alterations in cancer cells, along with a range of other genetically-based diseases. Reported today in the journal Nature Genetics, this technology has the potential to help with the diagnosis and future treatment of diseases such as cancer by testing for the presence of genetic changes across the whole genome.

The new technology – called whole genome array Comparative Genomic Hybridization (array CGH) – allows all of the DNA from the human genome to be laid out or arrayed on a microscope slide. The array is used to find sites of acquired genetic change that may help us understand the progression of normal cells towards cancer. The technique allows researchers to scan the entire genome in cancer cells to identify sites where there have been changes in the amount of DNA. Regions with abnormalities may harbor the location of genes responsible for cancer development or progression.

For cancer patients, this array technology may allow development of specific tests that diagnose cancer at an early stage, which in turn allows for earlier treatment. Since the technique is at least 12 times more sensitive than other existing methods for detecting very small genomic changes, it can also implicate genes that are not currently known to be involved in cancer.

This array works by assembling more than 32,000 fragments of normal human DNA, which are deposited as distinct dots onto a one inch by three inch glass slide, using a special printer. Tumour DNA is specially prepared with a light emitting dye and used as a probe to seek out the dot containing the corresponding region of normal DNA. The dye allows researchers to compare sample tumour DNA to normal DNA. The intensity of the coloured light from each spot determines whether there are abnormalities in the DNA of tumour cells. Yellow means no change, red means extra tumour DNA (more than normal) and green means a loss of DNA. Using a specially written software program, the identity of the altered fragments are compared to the human genome sequence to determine which genes are contained within those fragments.

This technique has advantages over current methods, as it only uses a small amount of tumour sample to assay the entire genome, which is particularly important when looking at the early stages of cancer.

The whole-genome slide technology is the result of a two-and-a-half year research project between Drs. Wan Lam, Calum MacAulay, and Marco Marra at the BC Cancer Agency, in collaboration with Dr. Donna Albertson at University of California at San Francisco.

Experiments with the prototype slides have revealed a number of novel genetic alterations of early stage cancers, as part of the Genome Canada and Genome BC funded Cancer Genomics project led by the BC Cancer Agency. Funding was also received from the BC Cancer Foundation, Province of British Columbia, the Canadian Institute of Health Research, the National Cancer Institute of Canada, and the US National Institute of Health.

Researchers are currently working to apply the whole-genome arrays to the study of genetic alterations in brain, breast, lung, lymphoma, oral, ovarian, and prostate cancers as well as inherited diseases.The BC Cancer Agency, a part of the Provincial Health Services Authority, is committed to reducing the incidence of cancer, reducing the mortality from cancer, and improving the quality of life of those living with cancer. It provides a comprehensive cancer control program for the people of British Columbia by working with community partners to deliver a range of oncology services, including prevention, early detection, diagnosis and treatment, research, education, supportive care, rehabilitation and palliative care. The BC Cancer Research Centre conducts research into the causes and cures for cancer.

For more information, please contact:
Nicole Adams
Public Relations Officer
BC Cancer Agency
(604) 877.6272