In 2016 the Bone Cancer Research Trust funded a study by Professor Dominique Heymann to investigate early events of recurrent disease and metastatic dissemination in osteosarcoma, this study has recently completed, and we are delighted to be able to with you some of the findings.

KEY FINDINGS OF THIS RESEARCH

Osteosarcoma tumours develop in a favourable “microenvironment” (like seeds growing in a well composted soil) which is composed of bone cells, blood vessels, and immune cells; these cells co-operate with each other and facilitate cancer growth and spread.

Macrophages are large white blood cells that play an important role in our immune system by engulfing unwanted particles. Osteosarcoma tissues are invaded by macrophages called “Tumour-Associated Macrophages” (TAMs).

TAMs can adopt two forms M1 or M2. M1-macrophages function as anti-tumour cells and M2 macrophages are pro-tumour regulators.

Professor Heymann studied samples of pre-chemotherapy osteosarcoma biopsies from patients with localised osteosarcoma and from patients with metastatic osteosarcoma.

The results indicate that M1-macrophages are present in non-metastatic patients; whereas M2 macrophages are predominant in metastatic osteosarcoma patients. This change of balance increases the formation of blood vessels around the tumour and facilitates the metastatic process.

The results from this study indicate that the presence of M1/M2 macrophages can be used as a marker for early metastasis from osteosarcoma biopsies and therefore identify patients at greater risk of disease spread.

It also emphasises the potential for treatment targets in osteosarcoma, which aim to increase M1 and/or reduce M2 macrophage production.