Today CD133 is the most commonly used marker for isolation of cancer stem cell (CSC) population from different tumors, mainly from various gliomas and carcinomas. Initial studies that showed ability of CD133-positive population to efficiently propagate tumor when injected into immune-compromised mice firstly were performed on brain tumors. However, subsequent studies have indicated the difficulty in isolating pure CSC populations. CD133+ melanoma cells are considered a subpopulation of CSC and play a critical role in recurrence. Moreover, CD133+ melanoma cells are immunogenic and can be used as an antimelanoma vaccination. In mice the vaccination with CD133+ melanoma cells mediated strong anti-tumor activity that resulted in the eradication of parental melanoma cells. In addition, it has also been shown that CD133+ melanoma cells preferentially express the RNA helicase DDX3X . As DDX3X also is an immunogenic protein, the same anti-melanoma vaccination strategy can be employed to give therapeutic antitumor immunity in mice.
