Similar data were reported by Gast et al. demonstrating that either injection of H2B-RFP B16F10 mouse melanoma cells into a GFP mouse or injection of H2B-RFP/Cre B16F10 cells into a R26R-stop-YFP transgenic mouse or injection of fl-dsRED-fl-GFP B16F10 cells into a Cre mouse resulted in the identification of tumor cell × normal cell hybrids [4]. Here, H2BC21 is linked to neoplasm.