Consistent with in vitro findings, SELENOI knockdown significantly reduced tumor growth in vivo (Figure 7L), and this effect was further enhanced by cisplatin treatment in the TUOS3–shSELENOI group (p < 0.05) (Figure 7M,N), with no observed adverse effects on mouse behavior, body weight, or organ pathology (Figures 7P and S5). This evidence concerns the gene SELENOI and neoplasm.