SCGB2A2 (secretoglobin family 2A member 2), also known as mammaglobin-1, is a secreted protein that belongs to the secretoglobin superfamily and serves as a breast-specific marker with significant clinical implications 1. The gene is localized to chromosome 11, a region frequently amplified in breast cancer 1. SCGB2A2 forms a covalent complex with lipophilin B (SCGB1D2) and shows concordant expression patterns with this partner protein across multiple tissue types 2. While initially characterized as breast-specific, expression analysis reveals SCGB2A2 is also abundantly expressed in gynecologic malignancies including endometrial, ovarian, and cervical cancers 2. The protein demonstrates significant association with estrogen receptor-positive breast tumors, suggesting hormone-related regulation 3. Functionally, SCGB2A2 overexpression reduces invasion, metastasis, and stemness in breast cancer cells 4. The gene's expression is controlled by complex transcriptional mechanisms involving distal regulatory elements, with a 345 bp minimal promoter region identified as crucial for tissue-specific expression 5. Clinically, SCGB2A2 serves as a prognostic marker, with its absence associated with non-progressive disease in melanoma and its presence correlating with better outcomes in breast cancer patients 64.