Research suggests that looking at genetic variation rather than the presence of individual mutations might be a better way to identify the most malignant tumours in childhood cancers, reports Medical News Today. The researchers, from Lund University in Sweden, say their study explains why – despite much research – for many types of childhood cancer it has been difficult to predict which patients are more likely to experience recurrence of their cancer.
It is already well-known that in adult cancers, genetic variation is greater in tumour cells than in healthy cells. This makes sense when one considers that in cancer, when cells divide, the chromosomes break up and recombine in odd ways, get muddled and end up in the wrong place. However, it has not been clear whether this also happens in childhood cancers and whether genetic variability in tumours is linked to aggressiveness.
The study confirms both of these are the case, as senior author David Gisselsson Nord, an associate professor at Lund who leads a group investigating genomic instability in childhood cancer, explains: "Tumours in children are also genetically unstable, and the greater the variation between the cells, the more malignant the cancer."
For their study, the team investigated 44 cases of Wilms’ tumour, the most common type of kidney cancer in children. All the young patients had received chemotherapy and most recovered, but unfortunately in some cases the cancer spread and the patients died. The study shows these patients had the most genetic variation in their tumours.
Previously, researchers had been trying to predict which cases were the most aggressive by looking for certain features – such as mutations – in a single sample from each patient, Gisselsson Nord explains. "However, when there is so much variation between the cells, one sample is not enough to determine the properties of the tumour," he adds.
Also, the team found it was enough to take a sample no bigger than a millimetre across and assess genetic variation between cells – the extent of "microvariations". Microvariations are much better predictors of the risk of metastasis and death than the presence of individual mutations, Gisselsson Nord, who concludes, "this is an entirely new way of assessing how dangerous a tumour is."
[link url="http://www.medicalnewstoday.com/articles/288681.php"]Full Medical News Today report[/link]
[link url="http://www.nature.com/ncomms/2015/150127/ncomms7125/full/ncomms7125.html"]Nature Communications abstract[/link]