KPL-1

KPL-1 is an authenticated human breast adenocarcinoma cell line established in 1995 from the malignant effusion of a patient with invasive ductal carcinoma. Classified within the luminal A molecular subtype, KPL-1 is estrogen receptor (ER)-positive, progesterone receptor (PR)-negative, and HER2-negative, with no amplification of c-erbB-2, c-myc, H-ras, or N-ras. Notably, it exhibits androgen receptor (AR) expression and differs from its parental MCF-7 background in MUC-1 and AR profiles, offering a distinct luminal model for comparative studies.

A defining advantage of KPL-1 is its estrogen-independent proliferation in vitro, making it particularly valuable for dissecting hormone-refractory mechanisms within an ER-positive context. The cells robustly express epithelial markers including cytokeratin, carcinoembryonic antigen, and CA 15-3, and secrete high levels of tissue polypeptide antigen (TPA) in a growth-phase-dependent manner—providing a quantifiable biomarker system that correlates directly with tumor burden in vivo.

KPL-1 demonstrates exceptional tumorigenicity, forming rapidly growing xenografts in female athymic nude mice with documented regional axillary lymph node metastasis. Its hypertriploid karyotype, authenticated STR profile, and extensive characterization across transcriptomic and pharmacogenomic platforms ensure experimental reproducibility. With its authenticated origin, defined luminal phenotype, hormone-independent growth capability, and proven in vivo metastatic potential, KPL-1 stands as a robust and versatile platform for investigating breast cancer biology, tumor-associated antigen kinetics, and therapeutic response.