CTTN expression was significantly higher in ER+/HER2+ breast cancer (Figure 1C, right), and high expression levels were significantly correlated with amplification of CTTN (r = 0.75, p < 0.001; Figure 1C, left) and HER2 expression (r = 0.2, p < 0.001; Figure 1D). This evidence concerns the gene ERBB2 and breast cancer.