Researchers have discovered how an incurable type of blood cancer develops from an often symptomless prior blood disorder.

The findings could lead to more effective treatments and ways to identify those most at risk of developing the cancer.

All patients diagnosed with myeloma, a cancer of the blood-producing bone marrow, first develop a relatively benign condition called 'monoclonal gammopathy of undetermined significance' or MGUS.

"Our findings show that very few changes are required for a MGUS patient to progress to myeloma as we now know virtually all patients with myeloma evolve from MGUS," said lead researcher Daniel Tennant from University of Birmingham in England.

"A drug that interferes with these initial metabolic changes could make very effective treatment for myeloma, so this is a very exciting discovery," Tennant explained.

MGUS is fairly common in the older population and only progresses to cancer in approximately one in 100 cases.

However, currently there is no way of accurately predicting which patients with MGUS are likely to go on to get myeloma.

It specifically affects antibody-producing white blood cells found in the bone marrow, called plasma cells.

For the study, the researchers compared the cellular chemistry of bone marrow and blood samples taken from patients with myeloma, patients with MGUS and healthy volunteers.

Surprisingly, the researchers found that the metabolic activity of the bone marrow of patients with MGUS was significantly different to plasma from healthy volunteers, but there were very few differences at all between the MGUS and myeloma samples.

The research team found over 200 products of metabolism differed between the healthy volunteers and patients with MGUS or myeloma, compared to just 26 differences between MGUS patients and myeloma patients.

The findings suggest that the biggest metabolic changes occur with the development of the symptomless condition MGUS and not with the later progression to myeloma.

The researchers believe that these small changes could drive the key shifts in the bone marrow required to support myeloma growth.

The study was published in Blood Cancer Journal.