Some Skin Cancers Start Growing in Hair Follicles

Some skin cancers may begin growing in the hair follicles, according to the findings of a new study published in Nature Communications.

In this study, researchers used a mouse model engineered to edit genes in follicular melanocyte stem cells, which in turn enabled them to implement genetic changes that made only melanocyte stem cells glow. They were subsequently able to confirm that melanoma cells can derive from melanocyte stem cells, which abnormally travel from hair follicles to enter the epidermis. The researchers of this study tracked the same cells as they multiplied and migrated deeper into the dermis.

Once they reached the dermis, the cells shed the markers and pigment that went with their follicular origins, presumably in response to local signals. They also acquired signatures like nerve cells and skin cells, with molecular characteristics similar to those noted in examinations of human melanoma tissue.

The research team confirmed that follicular melanocyte stem cells, even though they had cancer-causing genetic mutations, did not multiply or migrate to cause melanomas unless also exposed to endothelin (EDN) and WNT. These signaling proteins normally cause hairs to become longer and pigment cells to multiply in follicles.

“By confirming that oncogenic pigment cells in hair follicles are a bona fide source of melanoma, we have a better understanding of this cancer’s biology and new ideas about how to counter it,” says corresponding study author Mayumi Ito Suzuki, PhD, associate professor in the Ronald O. Perelman Department of Dermatology at NYU School of Medicine and Perlmutter Cancer Center in a press release about the study.

“Our mouse model is the first to demonstrate that follicular oncogenic melanocyte stem cells can establish melanomas, which promises to make it useful in identifying new diagnostics and treatments for melanoma,” says first study author Qi Sun, PhD, a postdoctoral fellow in Ito’s lab. “While our findings will require confirmation in further human testing, they argue that melanoma can arise in pigment stem cells originating both in follicles and in skin layers, such that some melanomas have multiple stem cells of origin.”