Our study is the first to utilise RS and machine learning to classify healthy volunteer samples alongside the four major breast cancer subtypes—Luminal A (HR+HER2−), Luminal B (HR+HER2+), HER2‐enriched (HR−HER2+), and TNBC (HR−HER2−)—at Stage Ia. The gene discussed is ERBB2; the disease is breast cancer.