Despite some immunotherapies been proven to be effective in treating melanoma brain metastases, researchers remain clueless about the reason behind the tumour’s spread to the brain. Now, through an extensive study of the cells inside melanoma brain metastases, researchers have unravelled details about the condition which could lead to the development of new therapies.

Melanoma is a type of skin cancer and brain metastasis is a condition that occurs when cancer spreads from the original site to the brain. Brain metastasis is behind most cancer-related deaths and most of the cases have been recorded with advanced melanoma.

In the study, published in Cell, researchers from the Columbia University Irving Medical Center began by sourcing frozen metastatic tumours from dozens of melanoma patients. “Such studies are typically performed on fresh brain samples, which are in short supply, drastically limiting the number of tumours that can be analysed. In contrast, we have many frozen melanoma samples in our tissue bank,” said study leader Benjamin Izar, MD, PhD, and assistant professor of medicine at the university.

Izar added that the technique allowed them to see the biology of the tumour and its microenvironment by helping them analyse tissues from patients who were not treated. After analysing genes in more than 1,00,000 individual cells, the researchers have noted that melanoma brain metastases were more chromosomally unstable than melanoma metastases in other parts of the body.

According to Johannes C. Melms, MD, a molecular postdoctoral fellow in the Izar lab and one of the study’s first authors, the chromosomal instability process triggers signalling pathways that end up facilitating the spread of cells and suppressing the immune system.

“Several experimental drugs that reduce chromosomal instability are going to be tested in humans soon. We now have a rationale to evaluate these drugs in patients with melanoma metastases in the brain,” said Melms.