Since the previous studies have not made it clear that what roles TRIM3 and TRIM16 play in breast tumors, in terms of oncogenic and tumor-suppressor activities, this study aimed to evaluate the expression of TRIM3 and TRIM16 genes in breast cancer tissue samples of Iranian women with unique demographic characteristics, prepared in Tehran, Iran, and to compare them to correspondent normal tissues, and also to investigate their roles in breast cancer and their relationship with cancer stage and metastasis. The gene discussed is TRIM3; the disease is breast cancer.