XIST and neoplasm: To determine if DOX-induced KD of XIST affects tumor growth in vivo, we injected SUM159 and MCF7 BCCs harboring the DOX-inducible shXIST hairpin sequence (V2THS_92229) into the #4 mammary fat pad (MFP) of 6-8-week-old female NOD/SCID mice, which were randomized in two cohorts (n = 5 per cohort) and fed with or without DOX-containing water for 11 weeks, starting one day after tumor cell injection.