Intriguingly, the almost complete inhibition of tumor growth observed in vivo (Fig. 6) was more dramatic than the approximately 40% reduction in tumor cell growth seen in vitro (Supplemental Fig. S6), suggesting that SFXN4 knockdown may exert additional effects that are only apparent in an in vivo context, such as the interaction of tumor cells with the microenvironment. Here, SFXN4 is linked to neoplasm.