Molecular analysis of breast cancer data from western populations reveal somatic copy number amplification of several oncogenes including FOXM1, CDH6, CXCL10 and NAAA oncogenes as well as deletions of tumor suppressor genes including TGM3 DMBT1 and MYO18B in patients with breast cancer onset before or at age 45 years. Here, DMBT1 is linked to breast cancer.