Studies that appear in the journal Nature have suggested that tiny pieces of genetic fragments called microRNA's, could help detect even hard-to-diagnose cancer.
Two studies, performed at the New York Harbour Laboratory found raised levels of specific microRNA coupled with highly distinct patterns of microRNA activity were linked to aggressive forms of blood cancer.
The discovery represents new technology and significantly a new direction in which exploiting them could play a role in almost every aspect of cancer medicine.
More than 200 different microRNAs have been identified but the function of only a few has been established. MicroRNAs appear to regulate a broad array of physiological and developmental processes.
RNA is generally regarded as the intermediate 'messenger' between genes and proteins, because DNA is transcribed into RNA before being translated into protein.
But recently, scientists have discovered that many genes are transcribed into RNA and never made into proteins. These 'non-coding' RNAs seem to act as regulators rather than messengers. They influence the expression of genes, for instance, by destroying coding RNA molecules so they cannot be translated into proteins.
In the study, the laboratory team used blood cancer (lymphoma) cells, specifically targeting a genetic segment containing a cluster of microRNA's called mir-17-92 and its levels of activity.
The scientists confirmed this theory by analysing tumour samples taken from sufferers. They produced similar results. Additional studies to further confirm their findings included breeding mice with increased activity in the key cluster area.
The mice developed lymphoma tumours more quickly than normal animals, and the tumours were more aggressive, killing all the animals within three months.
The scientists theorised that the activity of the microRNA's blocked the usual pattern of programmed cell death within a tumour, speeding up its growth, making it highly malignant.
Researcher Dr Gregory Hannon said in the study: "This is by no means a final answer about the role of microRNAs in cancer."
"But it's the first really definitive link where we can show with biological experiments that microRNAs can act as an oncogene," he added.
The study showed that scientists could use these profiles to diagnose the origin of tumours that are difficult to classify by the traditional method of looking at cell shape and character under a microscope.
MicroRNA profiling also worked better than existing genetic profiling methods, correctly diagnosing 12 of 17 tricky tumours. The existing method diagnosed only one of these tumours correctly.
Indeed, the discovery is set to have knock-on effects for treatment strategies, with suggestions that microRNAs are potentially therapeutic. They could be delivered to tumours, maybe in combination, or even along with chemotherapeutic drugs.