PROM1 and neoplasm: Schmohl et al. [124] developed heterodimeric bispecific single-chain variable fragment killer engagers (BiKEs) that simultaneously recognize the tumor-specific CD133 and CD16 on NK cells, and showed a significant increase in NK-mediated killing of human Caco-2 colorectal adenocarcinoma cells that overexpress CD133, as well as the enhancement of NK cell cytotoxicity against the NK-resistant human Burkitt's lymphoma Daudi cell line, in which less than 5% of cells express surface CD133.