Malignant melanoma can be one of the deadliest types of skin cancer due to its ability to spread to the brain. Unfortunately, it is also a “black box” as far as research goes since the manner in which metastatic cells are able to infiltrate the brain, lie dormant for months or years, before emerging as brain cancer has been largely unknown. A study from Tel Aviv University believes they may have cracked open the box and found out how melanoma in the skin can become melanoma on the brain.
The topic revolves around what are called “micro-tumor” cells, which in this case are melanoma cells that are too few and not reactive enough to be detected by modern medicine. These cells can spread through the body even as the primary melanoma is being removed and have the ability to spread into the brain. This state of “micrometastases” is only revealed when the cells begin dividing and a tumor grows enough to get spotted—but by then it is too late and inoperable. The Tel Aviv research involved breaking down how micrometastases in the brain forms and finding ways it could be detected.
Using mouse models, the researchers found that when the micro-tumor cells entered the brain, the immune system interpreted their presence as an injury. In response, the brain initiated the “astrogliosis” process—its standard inflammatory and repair reaction to damage or injury. Since the micro-tumor cells were not an actual injury, this process did not work as intended. Instead, the inflammation process gets hijacked by the micro-tumor cells and ends up allowing the cells to grow faster and reach further into the brain to get at blood vessels. All of this happens before full growth of the tumor begins in earnest, during the period where treatment is theoretically possible.
Breaking the black box of melanoma in this manner has some tantalizing, if still in-progress, possibilities. Most importantly is that, even if micro-tumor cells still can’t be directly detected, knowing how they interact with astrogliosis—which can—means that it may be possible to design detection tools capable of spotting micrometastases. More work is also being done to find a way to prevent the metastases in the first place rather than trying to treat it after-the-fact.
“TAU Research Opens the ‘Black Box’ of Malignant Melanoma,” Tel Aviv University web site, July 25, 2016; https://www.aftau.org/weblog-medicine–health?=&storyid4704=2283&ncs4704=3, last accessed July 26, 2016.