HOXB3 and breast cancer: By qRT-PCR, we confirmed that HOXB3 had the highest expression in the immortalized breast epithelial cell line MCF-10A, whereas expression was lower in the luminal breast cancer cell lines T47D and MCF-7 and the lowest in the triple negative breast cancer (TNBC) cell lines MDA-MB-231 and SUM-159 (Fig. 5A).