IHC of FFPE parental MDA-MB-231, C13, and C39 tumor xenografts confirmed greater Trop-2 expression in C13 relative to parental MDA-MB-231 with an even greater staining in C39, demonstrating that the higher Trop-2 levels in the clones is maintained in vivo (Figure 3A). The gene discussed is TACSTD2; the disease is neoplasm.