ESR1 and breast cancer: Stratifying the patient material based on ER expression, and the presence of lymph node metastasis we found that hCAP18 expression was significantly higher (p < 0.001) in ER-positive tumours (n = 38) with lymph node metastases than in tumours without lymph node metastasis (n = 42) associating the expression of hCAP18 with metastasis formation in breast cancer (Figure 1a).