PIPOX and breast cancer: Interestingly, Pipox is a sarcosine metabolism-related protein whose expression levels have recently been reported to significantly correlate with distinct molecular subtypes of breast cancer.27, 41–43 Excitingly, we found MDA-MB-231 breast cancer cells treated with sdRNA-93 inhibitor strongly suggest that Pipox represents a legitimate endogenous target of sdRNA-93 as our initial western blotting demonstrated a dose responsive increase in Pipox expression accompanying sdRNA-93 inhibition (Supplementary Fig. 2).