The researchers looked specifically at melanoma, one of the most aggressive skin cancers. Early diagnosis is essential for treatment. With more than 150,000 diagnoses, or four percent of all new cancer diagnoses in 2020, it is the sixth most common cancer in Europe.
Advanced technology allowed the researchers to study melanoma tumors at the level of individual cells. «We have been able to analyze the composition of tumors with an unprecedented resolution,» explains Jean-Christophe Marine (Center for Cancer Biology). “That has allowed us to identify a broad spectrum of cancer cells as well as normal cell types that infiltrate the tumors.”
The research team was able to determine that the proximity of endothelial cells allows cancer cells to grow tumors. Endothelial cells are very flat, closely connected cells, which are located, among other things, on the inside of the heart and the blood and lymphatic vessels.
“It’s a stunning discovery,” says Marine. “It suggests that blocking the communication between both cell types (endothelial cells and cancer cells, ed.) could be an attractive route to prevent tumor growth at an early stage.”
Marine’s team was also able to identify a cell type that is at the root of the metastatic spread, or the metastasis of melanoma cells to other vital organs. It is a very rare cell type, which makes up only two percent of a tumor.
“We were able to record that a small fraction of cells with invasive features and located deep in the tissue of the tumor are responsible for the metastatic lesion spread to other organs,” says Marine. “Once those cells started colonizing other organs like the lungs or the liver, they changed identities and started multiplying in those new locations.”
The observations are particularly important: the presence of this rare cell type in early skin tumors may predict the risk of further metastasis. Overall, the work of Marine’s research team may help predict the aggressiveness of early-stage melanoma. In the long run, this could lead to new strategies that could slow or even prevent tumor growth.
The insights found could also be translated to other forms of cancers and tumors. However, more research is needed. The results of the study have been published in the scientific journal Nature.