A number of studies have reported the existence of cancer stem cells in human melanomas, each one capable of producing a tumour. Boiko et al. examined a broad spectrum of clinical samples taken from melanomas and report that the neural crest stem-cell marker CD271 is a marker for cancer stem cells, allowing the identification and prospective isolation of melanoma cancer stem cells. In this work, the neural crest stem cell marker CD271 is implicated as a cancer stem cell marker, allowing identification and prospective isolation of melanoma cancer stem cells. The question of whether tumorigenic cancer stem cells exist in human melanomas has arisen in the last few years1. Here we show that in melanomas, tumour stem cells (MTSCs, for melanoma tumour stem cells) can be isolated prospectively as a highly enriched CD271+ MTSC population using a process that maximizes viable cell transplantation1,2. The tumours sampled in this study were taken from a broad spectrum of sites and stages. High-viability cells isolated by fluorescence-activated cell sorting and re-suspended in a matrigel vehicle were implanted into T-, B- and natural-killer-deficient Rag2−/−γc−/− mice. The CD271+ subset of cells was the tumour-initiating population in 90% (nine out of ten) of melanomas tested. Transplantation of isolated CD271+ melanoma cells into engrafted human skin or bone in Rag2−/−γc−/− mice resulted in melanoma; however, melanoma did not develop after transplantation of isolated CD271− cells. We also show that in mice, tumours derived from transplanted human CD271+ melanoma cells were capable of metastatsis in vivo. CD271+ melanoma cells lacked expression of TYR, MART1 and MAGE in 86%, 69% and 68% of melanoma patients, respectively, which helps to explain why T-cell therapies directed at these antigens usually result in only temporary tumour shrinkage.

Research from JAMA Otolaryngology–Head & Neck Surgery — Characteristics and Prognosis of Malignant External Otitis With Facial Paralysis