Common breast cancer biomarkers include proteins such as HER2 (Human Epidermal Growth Factor Receptor 2), CA15-3 (Cancer Antigen 15-3), and CEA (Carcinoembryonic Antigen), as well as genetic markers like BRCA1 and BRCA2 mutations and specific microRNAs. The gene discussed is CEACAM5; the disease is breast carcinoma.