NTRK1 and breast cancer: In regard to FAM83A expression in BC, previous transcriptomic and proteomic studies revealed that FAM83A is upregulated in HER2 + BCs, including those that are resistant to the HER2-targeted therapy trastuzumab [8, 36]. HER2 is amplified in about 30% of all breast cancer patients and is a member of the same receptor tyrosine kinase family as EGFR, the ErbB family.