Professor Katarzyna Leszczyńska, Head of the Laboratory of Tumour Hypoxia and Epigenomics at the Nencki Institute of Experimental Biology, Polish Academy of Sciences, has received the Prime Minister’s Award for outstanding scientific achievements in 2025.

The annual awards, presented by the Prime Minister, recognise outstanding achievements in scientific research. Professor Leszczyńska was honoured for her scientific work, which formed the basis of her habilitation and focuses on the role of tumour hypoxia in cancer progression and treatment resistance.

Hypoxia — a condition in which tissues are deprived of adequate oxygen — is one of the major challenges in modern cancer biology. Professor Leszczyńska’s research explores how low oxygen levels affect tumour development and contribute to resistance to cancer therapies, including radiotherapy.

“During my PhD at the University of Birmingham, I studied blood vessels in the context of their development within tumours. I then moved to Oxford for a postdoctoral fellowship, where I spent eight years investigating hypoxia — or oxygen deprivation — in cancer,” says Professor Leszczyńska.

The two areas of her research — tumour blood vessels and hypoxia — are closely connected. Solid tumours can grow rapidly, but their cells require oxygen and nutrients supplied through the bloodstream. As a result, tumours stimulate the formation of new blood vessels within the tumour mass.

“Tumours promote the development of their own blood vessel network. However, these vessels grow so rapidly that they cannot keep pace with tumour growth and do not function properly. They can become distorted, enlarged or blocked, and may even develop blind ends. As a result, areas that are poorly supplied with blood become hypoxic,” explains Professor Leszczyńska.

Hypoxia triggers a range of molecular changes in tumour cells and can significantly reduce the effectiveness of radiotherapy.

“This is what I focused on in my research. Among other things, I studied p53, a protein that plays a key role in suppressing tumour development. p53 is also activated under hypoxic conditions. The problem is that in more than half of cancers, the p53 protein is mutated. When it is damaged, it can no longer effectively eliminate cancer cells,” she explains.

One of the studies included in Professor Leszczyńska’s habilitation examined how p53 triggers programmed cell death, or apoptosis, under hypoxic conditions, and how this response differs from the mechanisms activated by radiotherapy and chemotherapy.

“We showed that under hypoxia, p53 activates a different set of genes involved in apoptosis than it does in response to radiotherapy,” says Professor Leszczyńska.

Hypoxia can activate genes that limit cell survival, ultimately contributing to cell death. These mechanisms may offer new opportunities for the development of cancer therapies.

“We were able to show that, in cells with defective p53, it is possible to use inhibitors that mimic the function of genes normally activated by p53. In this way, we were able to increase the effectiveness of radiotherapy,” she adds.

Professor Leszczyńska’s research has significant translational potential, with findings that could ultimately contribute to the development of new approaches to cancer treatment.

One of the areas she is currently investigating is paediatric high-grade glioma, including tumours arising in the brainstem. Because of their critical location, these tumours cannot generally be surgically removed. Radiotherapy therefore plays an important role in their treatment, while hypoxia within the tumour may contribute to treatment resistance.

Professor Leszczyńska is working on these questions in collaboration with clinicians at the Children’s Memorial Health Institute in Warsaw. Her current research also addresses the role of hypoxia in the tumour microenvironment and epigenetic regulation in paediatric high-grade gliomas, building on her long-standing research into the molecular mechanisms underlying tumour hypoxia.

The Prime Minister’s Awards have been presented for the 33rd time. This year, 44 individuals and one research team were honoured. Researchers from the University of Warsaw received the largest number of awards, with eight laureates. In total, the awards went to representatives of 31 institutions.