New fluorescent tracer ‘lights up’ a range of solid tumours

In an initial study of patients with different types of cancer, a newly developed fluorescent tracer that ‘lights up’ tumours was found to be efficient and safe and to have wide clinical application, regardless of the tumour type. This pH-sensitive tracer could be activated from the ‘off-state’ to the ‘on-state’ by the low acidity in the various tumours studied. The new tracer has now been clinically tested in patients with breast cancer, oesophageal cancer, bowel cancer and head and neck cancer.

The research was carried out at the UMCG by physician-researchers Floris Voskuil and Pieter Steinkamp under the leadership of Professor Go van Dam. The study was a collaboration with the University of Texas Southwestern (Dallas, USA), the Martini Hospital Groningen and two start-up companies OncoNano Medicine (Dallas, USA) and TRACER BV (a UMC Groningen start-up). The study findings are being published on the 26th of June in the authoritative journal Nature Communications. Fluorescence imaging has been widely studied in cancer patients at the UMCG surgical oncology ward since 2011. This has frequently involved the use of tumour-specific fluorescent tracers that are produced in-house. Until now, one drawback was the absence of a ‘one-size-fits-all’ tracer that will always light up, regardless of the type of tumour.

First ‘one-size-fits-all’ tracer

Almost 100 years ago, Professor Warburg pointed out that tumours have an acidic environment because of the altered metabolism of fast-growing cancer cells. This is known as the Warburg effect. Current standard PET imaging technologies, which are based on this altered metabolism, use radioactive glucose. Researchers in Dallas, USA have focused on the acidic environment in tumours and have developed a pH-sensitive, fluorescent nanoparticle. Irrespective of the tumour type, this tracer can use the low pH present in all tumours that develop in organs to turn itself ‘on’. These American researchers have been the first to develop a ‘one-size-fits-all’ fluorescent tracer, called ONM-100.

Available sooner in clinics

The advantage of this new, widely deployable ‘on-off’ fluorescent tracer is that it can be used for image-guided surgery and pathology for many different types of tumour. This will make it more readily available for further clinical implementation now that the initial experiences with patients have been positive. A Phase 2 study involving TRACER BV is currently taking place in the United States. More patients are taking part in this study than in the studies carried out so far. The first results are expected at the end of the year.