Leendert Looijenga was trained as a medical cell biologist at the University of Groningen. During his graduation internship he analyzed the DNA of germ cell tissue after chemotherapy. That’s where his interest in the combination of development biology and the emergence of cancer started. Germ cells are precursors of the sex cells - sperm cells in boys and eggs in girls. ‘If the embryonic development of the testes or the ovaries does not go well, infertility or a tumor may occur. Hence the combination of germ cell tumors and fertility in my professorship’, explains Looijenga. ‘Those subjects are actually two sides of the same coin.’
Optimal treatment
Germ cell tumors are relatively rare, around 15 children in the Netherlands are diagnosed with the disease each year. Germ cell tumors can occur in the sex organs, or in the head or other places in the body. They occur at a young age, from newborns to young adults. The disease can be treated well in many children and young people. The current treatment consists of surgery, possibly with radiotherapy and chemotherapy. ‘The main goal in healthcare and research into germ cell tumors is giving optimum treatment,’ says Looijenga. ‘A child still has their whole life ahead of them. That means that we want to prevent both under- and overtreatment. We have to give enough treatment to make sure that the cancer cells die, and do not become insensitive to therapy. But you don't want to overtreat; this can lead to unnecessary side effects and late effects.’
After his education in Groningen, Looijenga came to Rotterdam via Leiden University. He started his own research group focused on germ cell tumors at the then Dr. Daniel den Hoed Kliniek, which eventually became part of Erasmus MC. In 2005 he was appointed there as a professor of Translational Patho-oncology. In 2018, as a specialist in the field of a tumor that occurs in children and young adults, Looijenga started as a research group leader in the Princess Máxima Center, which opened its doors that year.
Mapping out germ cell tumors
‘The current treatment for germ cell tumors works well for 90% of children and young adults. But the late effects of in particular platinum chemotherapy, such as cisplatin, are really becoming clear now’, says Looijenga. ‘To reduce these, it is important to investigate whether we can achieve the same survival with less intensive treatment. And for patients whose standard treatment is not working now, we are looking for other effective therapies. With that aim, we’re making a detailed study of the properties of germ cell tumors that are insensitive to therapy. And we’re developing ways to measure the sensitivity of the tumor cells before treatment. Ultimately, we hope to prevent damage to fertility. Also for children who are at risk of infertility from treatment for a different form of cancer.’
Collaboration between lab and clinic
In his research, Looijenga combines insights from developmental biology with the various disciplines from adult and childhood oncology. ‘Based on our knowledge of the normal development and properties of germ cells, we have developed a system to pick out different types of germ cell tumors. This is increasingly being used in the clinic, and will lead to better choices around the best treatment for children and young people with a germ cell tumor.’
This type of interaction between the laboratory and the clinic is essential, says Looijenga. In his professorship within the UMC Utrecht, he wants to boost this collaboration. ‘We can further shape our research based on registrations and analyses of tissue in our biobank, and from questions in the clinic. Both in the collaboration within our research hospital and with the UMC Utrecht. The set-up of the joint expertise center for germ cell tumors is of great value. Together we can turn the knowledge about germ cell tumors into clinical applications, in order to move the dial for the treatment for children and young adults.’
Prof. dr. Leendert Looijenga was appointed as a professor of Translational germ cell oncology and fertility at the Faculty of Medicine at Utrecht University on July 15, 2023. His research is a collaboration between the Princess Máxima Center and the Cancer and Child Health strategic programs at the UMC Utrecht. Prof. Looijenga’s inaugural lecture will take place at a later date.