Using RT-qPCR, we examined the relative expression level of gene B4GALNT2 mRNA in five different breast cancer cell lines, namely MDA-MB-231 (ER-/PR-/HER2-), T47D (ER+/PR+/HER2-), MCF7 (ER+/PR+/HER2-), SK-BR-3 (ER-/PR-/HER2+) and HCC1937 (ER-/PR-/HER2-) (Figure 1C) (63). This evidence concerns the gene ERBB2 and breast cancer.