MYC and breast cancer: We also noted that in the PDXs, the best responders to TAK-243 (HCI-001 and UCD52) had higher levels of c-MYC compared to the other PDXs tested (VCU-BC-01, VCU-BC-02, and VCU-BC-03) (Fig. 5B), suggesting that c-MYC expression might correlate with sensitivity to TAK-243 in in vivo as well.