ERBB2 and breast cancer: Palomeras et al. demonstrated that genes such as transforming growth factor beta-induced (TGFBI), C-X-C motif chemokine ligand 2 (CXCL2), and solute carrier family 38 member 1 (SLC38A1) are consistently hypermethylated and downregulated in trastuzumab-resistant HER2+ breast cancer, with TGFBI showing the highest silencing at both the mRNA and protein levels[93].