Detection of tumor cells in leukapheresis products from patients with breast cancer using immunocytochemical staining method

Abstract 

We used a combination of 4 monoclonal antibodies (BM7, BM8 against MUC1, 5D3 aganist CK8,18,19 and HEA125 against human epithelial antigen) and a sensitive immunocytochemical staining using cytospin preparation to identify breast tumor cells in leukapheresis products (LP). This assay allowed detection of one tumor cell in 1×10⁶ mononuclear cells (MC). In clinical specimens, tumor cells were detected in LP from 6 of 42 (14.3%) patients in the adjuvant treatment group, from 2 of 11 (18.2%) patients in the neoadjuvant treatment group and from 9 of 43 (20.1%) in the group of patients with metastatic disease. Tumor cell counts ranged from 0.25–5 cells in 1×10⁶ normal cells per LP. The median tumor cell concentration was higher in specimens from patients with metastatic disease (median=0.96) than in specimens from patients in the adjuvant and neoadjuvant treament groups (median=0.5 and 0.75). No significant differences between the epithelial cell positive group and the epithelial cell negative group with respect to tumor size, lymph nodes involvement, tumor grade, histological type and receptor were found. We conclude that immunocytochemical staining of cytospin preparation is a sensitive and simple method to detect and quantitate breast cancer cells in LP.