TWIST1 and B-cell chronic lymphocytic leukemia: As mentioned above, SAL was shown to act on tumor stem cells as well, with a lower IC50 than the one found here for Jurkat, MEF or B-CLL cells.1 In particular, Gupta et al.1 showed (and we confirmed (not shown)) that immortalized human mammary epithelial cells (HMLE) ectopically expressing the transcription factor Twist and therefore forced to undergo epithelial–mesenchymal transition are sensitive to SAL, displaying an IC50 of around 1 μM regarding cell viability.