CELF1 and neoplasm: Three of the most salient possibilities are: (i) that the former experiments were conducted in the context of constitutive CELF1 knockdown a priori, (ii) the inherent aggressivity of the 4T1 obscures robust effects in the timeframe between doxycycline-mediated induction and primary tumor resection, or simply, (iii) that there are as-yet-uncharacterized differences in how CELF1 manipulation influences the behavior of the two models.