As expected, subtype distribution differed in HER2-low breast cancer according to ERBB2 levels (p < 0.001) with the T2-3 group being more enriched with Luminal A, Luminal B and HER2-E subtypes (51.5%, 34.9%, and 6.3%) compared to the T1 group (31.7%, 15.8%, and 3.6%). The gene discussed is ERBB2; the disease is breast cancer.