B4GALNT2 and breast cancer: This prompted us (i) to examine correlations between knockdown of this gene and the malignancy of breast cancer by carrying out lentivirus-assisted B4GALNT2 gene knockdown experiments in model TNBC cell lines of HCC1937 and MDA-MB-231, and (ii) to investigate the possible mechanisms in play in the downstream pathway of the B4GALNT2 gene by conducting co-immunoprecipitation (Co-IP) mass spectroscopy-assisted analysis and performing in-vitro tests.