asa [dot] hansdotter [at] med [dot] lu [dot] se (Åsa Hansdotter)
- published 29 March 2023
There is a large carton of chicken eggs on the bench in Sofie Mohlin's laboratory. They have been delivered during the morning and soon they will be placed in the 37-degree heat of the incubator so that the embryo can develop. Already 42 hours after fertilization, researchers can begin their experiments to study how neuroblastoma develops.
Sofie Mohlin is an Associate Professor in Molecular Physiology and a researcher at Lund Stem Cell Center at Lund University. Her research focuses on neuroblastoma, a type of cancer that forms in certain types of nerve tissues and which mainly affects children under 5 years of age and is rare in adults. In Sweden, around 20 children are diagnosed with neuroblastomas each year. In some cases, children have already developed neuroblastoma when they are in the womb. The tumors grow in the sympathetic nervous system, which begins in the adrenal gland and follows the spine with its nerve fibers. Of all cancer cases in children, neuroblastoma accounts for about seven to ten percent, but 15 percent of deaths, so the prognosis is poor for many of those with a diagnosis.
“In children, for obvious reasons, there are no environmental or lifestyle factors that can trigger cancer, meaning that the disease is therefore hereditary, which is unusual, or spontaneous - that is, due to pure "bad luck." But when, how, and where during the development of the nervous system that transformation from normal growth to cancer development occurs, we do not know. We are therefore trying to understand which genetic changes are behind it,” says Sofie Mohlin.
Studying fetal development "in ovo"
To do this, she needs to study what happens during fetal development. Sofie Mohlin is the only researcher at Lund University and one of two research groups in the whole of Sweden, that use chicken embryos in their research. The benefits of using eggs are many.
“The nervous system of chicken embryos is similar to that of humans, and the studies can take place "in ovo" - in the egg's natural environment with nutrition and oxygen. The development process of chickens is also much faster than that of mice, and research can begin as soons as the embryo starts to grow after fertilization. It is also in line with the 3R principle, as we use a refined technology while not harming adult animals”.
The advantage is also that there is a large supply of eggs and, compared to mice, they are very cheap. Since according to Swedish guidelines, chickens are not considered vertebrates until they are 14 days old, the ethical rules surrounding the studies are even fewer than those surrounding, for example, mice or humans.
“Although chickens and humans share 75 percent of their gene set, the disadvantage is of course that both mice and chickens are of the "wrong species" and that the results therefore cannot be directly transferred to humans. We must therefore ensure our results in several ways that ensure reliability,” notes Sofie Mohlin.
It was after her postdoc studies in the USA that Sofie Mohlin was inspired to use chicken embryos in her research, and she decided to set up her laboratory in Sweden. With her first grant award, she bought a microscope and then it became detective work to find an egg supplier. It turned out that the solution was closer than she could imagine, as a colleague had chickens at home on his farm.
By opening the top of the egg, Sofie Mohlin and her research group can study fetal development from a new angle and have succeeded in identifying a gene that is important for the development of a healthy nervous system. When this gene changes, the cells that give rise to cancer are affected. The research team has also found a gene that helps prevent neuroblastoma from occurring. The gene's task is to suppress tumors and when the gene is turned off for some reason, the regulatory mechanism disappears, and the result is a very aggressive form of neuroblastoma that not many children survive.
“With a deeper understanding of the origin of the tumor, we may be able to develop biomarkers that can help us diagnose children earlier and understand what prognosis they have. In the long run, we hope that this new knowledge can result in new treatment therapies for neuroblastoma,” concludes Sofie Mohlin.
Associate Professor, PhD
Divison of Pediatrics,
Department of Clinical Sciences
BMC B11 | Lund University
223 81 Lund, Sweden
Phone:+46 46 222 64 18 Mail: Sofie [dot] Mohlin [at] med [dot] lu [dot] se (Sofie[dot]Mohlin[at]med[dot]lu[dot]se)