Importantly, analysis of the GSE12276 cohort of breast cancer patients, where 204 women were followed for sites of metastatic relapse, showed that higher KRT81 expression levels in the primary tumor were significantly associated with a shorter lung and brain metastasis‐free survival (Figure 1B,C, respectively) but not bone metastasis‐free survival (Figure 1D), further indicating the relevance of our CTC derived data and demonstrating the significance of KRT81 in metastasis. This evidence concerns the gene KRT81 and breast cancer.