Consistent with the previous statement, earlier studies on the molecular characterization of HER2-low tumors have indicated that this subgroup frequently exhibits a mutational profile closely aligned with a luminal phenotype, supported by their elevated prevalence of PIK3CA and GATA3 mutations, as well as a higher subclassification within the luminal A and luminal B subtypes according to PAM50 [29]; this aligns with our findings, where the luminal-like subtypes were also the predominant tumor classification among HER2-low tumors. The gene discussed is ERBB2; the disease is neoplasm.