Dormant tumor cells in ret transgenic mouse melanoma model and their interaction with memory T cells

The study investigated dormant tumor cells in a ret transgenic mouse melanoma model, focusing on their interaction with memory CD8+ T cells. It was found that TRP-2+CD133+ melanoma cells, representing less than 1.5% of cells in primary tumors, were mostly dormant, as indicated by negative Ki67 expression. These cells were present in the bone marrow (BM) of 40% of mice without macroscopic tumors and all tumor-bearing mice. Despite the presence of memory CD8+ T cells, their interaction with dormant melanoma cells was limited, with less than 15% of T cells engaging with these cells. The study concluded that the tumor microenvironment might suppress CD8+ T cell reactivity, as evidenced by the lack of perforin and IFN-g production in T cells interacting with melanoma cells. This research highlighted the existence of a subpopulation of dormant CD133+ melanoma cells capable of interacting with CD8+ T cells in the BM of tumor-bearing mice.