Currently, detecting HER2 status primarily relies on invasive methods such as IHC or FISH, which involve tissue samples.[8] However, there is a lack of agreement in HER2 status between crude needle aspiration biopsies and subsequent excisional biopsies of the same breast cancer, with a range of 81% to 96%.[9,10] Moreover, these techniques are limited by intra-tumor heterogeneity, which is considered a significant factor in cancer treatment failure and poor prognosis.[11] Additionally, the small amount of biopsied tissue may not fully represent the overall characteristics of the tumor. The gene discussed is ERBB2; the disease is cancer.