The complex sugars attached to cancer cells may offer a faster and more accurate way of diagnosing the disease without the need for surgical biopsies
SUGAR COULD BE the answer for cheaper, simpler and faster cancer diagnosis. Dublin researchers are developing new scientific tools capable of detecting the tiny amounts of sugars produced by cancer cells.
Cancer cells express different sets of proteins than normal cells, and they also have different types and numbers of sugar molecules attached to them. Cancer cells use these to bind with and communicate with one another. This means that normal and cancerous cells can be distinguished by the kinds of sugar molecules present, explains UCD's Prof Pauline Rudd.
"We have found that there are alterations in sugars attached to proteins in blood serum from all cancers we have looked at and some of these appear to be early markers of the disease processes," says Rudd, who is leading the National Institute for Bioprocessing Research and Training (Nibrt) Dublin-Oxford Glycobiology Laboratory in UCD.
"What is more, we have been able to isolate several sugar-linked variants of particular proteins which are associated with different types of cancer, including prostate, pancreatic, ovarian and breast cancers," she says.
Cancer cells also use sugars to hide from the body's immune system so that they can travel from the primary site to seed new cancers in other organs, a process called metastasis. This means that the levels and types of sugars produced can also be used to monitor disease progression and how the patient is responding to therapy, she says.
There is a great need for more accurate biomarkers, like these sugars, because many of the biomarkers currently in use are not very accurate.
"PSA is used in the diagnosis of prostate cancer, for example, but it is not great," Rudd says.
PSA or prostate specific antigen is a protein produced by cells in the prostate. The higher the level of PSA, the more likely it is that cancer is present. But there are other reasons for elevated PSA levels, which means that a high PSA is not sufficient for diagnosis.
If, however, Rudd's team can pin down sugar variants specific to disease, they could be used in combination with biomarkers like PSA to provide more accurate diagnoses.
"It is unlikely that we would use the sugars on their own. They would most likely be used in combination with a panel of other biomarkers," Rudd says.
Mark Lawlor, a professor of haematology at Trinity College, agrees that these sugars offer an exciting new possibility for cancer diagnosis.
"If it proves possible to pin down biomarkers like these sugars that are specific to disease, and show that they accurately reflect what is happening in tumour tissue, then we could start to move away from the traditional biopsy. Blood and urine samples could be used instead, which would be easier for everyone especially the patient," he says.
Rudd's team is developing sophisticated technology to analyse the sugars. "We are developing unique computer programmes and unique databases that we hope will lead to the development of a simple diagnostic technique. Such a technique could provide a less expensive, less complicated alternative to mass spectroscopy," she says. Mass spectro- scopy converts molecules to ions and the mass-to-charge ratio is measured.
Rudd's team was originally based in Oxford but decided to move to Dublin to avail of the facilities provided by Nibrt, an organisation set up specifically to engender co-operation between industry and academia.
"We had got to the stage where we were ready for commercialisation. Ireland has such a visionary policy regarding enabling the best academic researchers to collaborate with industry. It would have been impossible to do in Oxford what we have done in Ireland on anything like the same scale. It has been very good for us," she said.