For example, CD44v6-positive exosomes secreted by pancreatic and colorectal cancer cells promote cancer invasion [10], CD44v8-10 mRNA in patient serum exosomes can be a diagnostic marker for docetaxel-resistant prostate cancer [11], CD44 in exosomes secreted by gastric cancer cells promotes lymph node metastasis [12], CD44 in exosomes secreted by highly metastatic ovarian cancer cells promotes the invasion of low metastatic ovarian cancer [13], and CD44 in the exosome secreted by breast cancer cells treated with doxorubicin CD44 promotes chemotherapy resistance [14]. Here, CD44 is linked to breast cancer.