These findings are consistent with several previous studies on breast cancer, non‐small cell lung cancer, ovarian cancer and pancreatic ductal adenocarcinoma, where high levels of CCL18 in blood has been reported to be associated with an increased occurrence of metastasis and tumour invasion, which results in poor prognosis.10, 22, 36, 51 Cancer metastasis begins with cancer cell migration or invasive growth, which then penetrates through nearby lymphatic or vascular wall. This evidence concerns the gene CCL18 and breast cancer.