CEMIP and breast cancer: According to the previous study, the brain metastatic small EVs CEMIP was highly enriched in small EVs of serum origin from patients surviving brain metastasis from breast cancer (Rodrigues et al., 2019), and AnxA2 was positively correlated with the invasiveness of breast cancer cells, implying that these two types of proteins could be tumor biomarkers (Maji et al., 2017).