Researchers from Tel Aviv University believe they have made a landmark discovery and unraveled the metastatic mechanism of melanoma—the very process behind why this deadly disease is so feared. The findings relate to how melanoma tumors cause the changes in the lower layers of skin necessary for spreading elsewhere in the body and work is already underway to devise means of shutting this process off.
In Brief: Metastasis
Metastasis is the process by which cancer cells from one area of the body spread to and form tumors in other, unconnected regions. While some tumors, like those in the brain or lungs, can cause serious damage or death on their own, others are relatively harmless until they reach the metastatic stage. Melanoma is considered the most dangerous type of skin cancer because it is highly aggressive and can metastasize more easily compared to other skin tumors. To put things (extremely) simply, without metastasis, a melanoma is basically just an over-excited mole.
Melanomas form in the epidermis of the skin—the surface layer—and don’t become metastatic until they penetrate into the lower dermis. This is because the epidermis has no access to the blood vessels that are abundant in the dermis, so there is no way for the tumor cells to have access to the rest of the body.
The TAU researchers looked at the interactions between melanomas and the dermis and found that, prior to metastasis, the melanoma cells would release vesicles (sacs) filled with micro RNA. These vesicles would enter the dermis and induce changes that made the layer more receptive to receiving and transporting the cancer cells.
Based on this finding, the current hope is that finding a way to stop this sort of “groundwork” from being laid might prevent the melanoma from being able to metastasize. The TAU researchers made progress on this front by finding two chemicals, called SB202190 and U0126. The first chemical shows the ability to stop the vesicles from being sent to the dermis and the second shows the potential to stop the dermal changes the vesicles are meant to trigger. Rounding up the findings is the idea that the changes in the dermis itself could be used as a sort of early diagnostic marker for melanoma cases.
What This Means
Melanoma is an undeniably deadly disease and is expected to kill around 10,130 people in the United States during 2016 alone. Metastasis is key to the cancer’s lethal potential and the promise of being able to stop it in its tracks would be an undeniable boon for medicine. While this research should be encouraged, it is also important to understand the findings in their proper context.
Assuming that metastasis truly can’t occur or would be noticeably impeded if the vesicle process was blocked, keep in mind that a chemical working in a Petri dish environment doesn’t automatically mean it will work in a living person or animal. The TAU findings are impressive and, if confirmed, rightly count as a breakthrough; and the translation of these findings to potential patient use is a process that must be given time to unfold.
“Key statistics for melanoma skin cancer,” American Cancer Society web site, last reviewed May 20, 2016; http://www.cancer.org/cancer/skincancer-melanoma/detailedguide/melanoma-skin-cancer-key-statistics, last accessed August 23, 2016.
Dror, S., et al., “Melanoma miRNA trafficking controls tumour primary niche formation,” Nature Cell Biology, 2016; 10.1038/ncb3399.