CD34 and breast cancer: Above all, statistical analysis showed that ST6GALNAC5 only closely connected with BM but not with lung metastasis or bone metastasis.124 Utilizing the established CD34+ derived human BBB model in vitro, they found ST6GALNAC5 cDNA expression leads to a decrease of the interaction between MDA‐MB‐231 and the CD34+ derived human BBB model.125 In consequence, ST6GALNAC5 does not seem to be a mediator which promotes breast cancer cell interaction with the human BBB.