Established from the pleural fluid of a 50-year-old Japanese woman with ductal carcinoma of the breast with a predominant intraductal component in 1992; cells were described to express estrogen, but not progesteron receptors and to secrete tissue polypeptide antigen; however, DNA fingerprinting analysis at the Creative Bioarray showed cross-contamination with cell line MCF-7; MCF-7 was established from the pleural effusion of a 69-year-old Caucasian woman with metastatic mammary carcinoma