Human mammary epithelial cells have different proliferative statuses and demonstrate a close relationshipwith age and cell proliferation. Research on this topic could help understand the occurrence, progression andprognosis of breast cancer. In this article, using significance analysis of a microarray algorithm, we analyzedgene expression profiles of human mammary epithelial cells of different proliferative statuses and different agegroups. The results showed there were significant differences in gene expression in the same proliferation statusbetween elderly and young groups. Three common differentially expressed genes were found to dynamicallychange with the proliferation status and to be closely related to tumorigenesis. We also found elderly group hadless status-related differential genes from actively proliferating status to intermediate status and more statusrelateddifferential genes from intermediate status than the young group. Finally, functional enrichment analysesallowed evaluation of the detailed roles of these differentially-expressed genes in tumor progression.