Oral cancers are the most common malignant tumours in the head and neck region, causing more than 188,000 deaths worldwide each year. Unlike in many other cancers, even small and early-stage tumours in oral cancer can lead to death. In Finland, where the study was conducted, up to a fifth of patients treated in the early stages later die from the disease.

The research team from the University of Turku and the InFLAMES research flagship used early-stage oral cancer samples collected from approximately 300 Finnish patients to study the properties of various defence and structural cells found in the tumour tissue. By studying multiple different protein markers, the researchers made the surprising discovery that some tumours showed a higher number of proliferating lymphatic vessels than normal. The high number of proliferating lymphatic vessels predicted cancer recurrence and death better than any other previously known risk factor for oral cancer.

Lymphatic vessels are normally present in the mouth, but in a healthy oral cavity, their cells rarely divide and marker proteins indicating this process are not usually seen.

"It is crucial to identify aggressive forms of the disease at the diagnostic stage to ensure that the increased risk of cancer recurrence and death can be addressed when planning the treatment. Currently, local oral cancer treatment mainly involves surgery, and there are no precise methods for targeting adjuvant therapies. We need biomarkers so that we can treat high-risk patients more effectively and avoid exposing patients with a better prognosis to the potentially serious adverse effects of adjuvant therapies,” says the lead author of the study Joni Näsiaho, a Doctoral Researcher at the University of Turku and a physician specialising in oncology.

“We are excited about the results and believe that the findings could also be applied as a practical tool for clinical use. Furthermore, it would be interesting to find out whether the marker we discovered has a similar predictive value in other cancer groups,” says Näsiaho.

The study was published in the prestigious medical journal Cell Reports Medicine. The work was funded by the Research Council of Finland, the Cancer Foundation Finland, and the Finnish Government research funding, and was carried out at the MediCity Research Laboratory of the University of Turku in the group of Professor, InFLAMES group leader Marko Salmi. In addition, three ear, nose and throat specialists who treat and study oral cancer in the Turku University Hospital also participated in the study.