New technologies are giving scientists an unprecedented view of what is going on inside cells, providing better diagnosis of illness but also new treatment options, delegates to the Belfast cancer conference were told.
A number of Irish and US researchers yesterday discussed "DNA chip" technology, which combines advanced genetics with high-powered computer systems. DNA chips exposed to a tissue sample can now screen simultaneously for nearly 20,000 genes in a single operation.
"Essentially a new telescope has been invented to give you a view of genetic expression inside the cell," said Dr Louis Staudt, a senior investigator in the US National Cancer Institute. The system could give a "gene expression profile" for any disease and was providing detailed information about biochemical changes that take place during disease progression. This in turn was changing the way doctors diagnosed and treated diseases. While there might be a single overall diagnosis, the disease at the biochemical level could subdivide into specific types that demanded specific treatments.
Earlier, Prof Tom Cotter, professor of biochemistry at UCC, discussed a number of new approaches in the treatment of cancer. They each depended heavily on our growing understanding of the complex chemical interactions taking place inside cells. He described "anti-sense" technology in which a chemical process linked to cancer was first identified and described. The object was then to develop counteracting chemicals that could interfere with the cancer process. An example, he said, was chronic myeloid leukaemia in which an excess of certain blood cells was produced due to a mutation in a particular gene. The mutation blocked a signal which tells blood cells when to die, causing them to live too long. The anti-sense approach was to identify the missing signal and reintroduce it, encouraging the aberrant cells to go back into their normal pattern of cell death.
Another approach involved "gene correction". It was now known that there were a number of genes involved in tumour suppression, such as the p53 gene. If their activity was blocked due to a mutation then cancers might occur. Gene replacement or correction involved finding ways to replace the mutated gene with its normal version, and so replace the missing tumour suppression factors.
A highly complex area of research involved studying the signalling pathways used within the cell. "This really is a black box," Prof Cotter said. "We really know very little about the events that drive this process."
There was a "maze" of signalling events inside the cell. Sometimes genes were turned on inappropriately, leading to cancers, and other times essential genes were switched off, cutting off substances such as tumour suppressers. The new DNA chip technologies were valuable in helping to unravel this maze of signals.