CD34 and melanoma: Proteins associated with stem and progenitor cells are also detected in melanoma and include cancer testis antigens (Simpson et al., 2005; Velazquez et al., 2007), bone morphogenetic proteins (Hsu et al., 2008; Rothhammer et al., 2007), Notch receptors (Balint et al., 2005), Wnt proteins (Weeraratna et al., 2002), or specific stem cell–associated markers, such as multidrug resistance transporters of the ABC family, CD133, CD166, CD34, Nestin, and c-Kit 2 (Frank et al., 2005; Laga et al., 2010).