Flow cytometric enumeration and kinetic analysis of inflammatory cell populations in breast carcinomas

Inflammatory cell populations were quantitated in 76 consecutive mechanically dissociated clinical breast carcinoma specimens using multiparameter, two-color (PI-cytokeratin/FITC, PI-LCA/FITC) flow cytometric analysis. The percent LCA-positive events varied from 1.3-62.5% (mean = 11%) and correlated with degree of histologic inflammatory cell infiltrate (mild-5.8% LCA + events vs. marked-35.9% LCA + events, P < 0.001), abnormal DNA content (diploid range - 4.6% LCA + events vs. aneuploid - 13.3% LCA + events, P = 0.003) and poor tumor differentiation (well-moderate - 6.5% LCA + events vs. poor - 19.9% LCA + events, P = 0.001). Synthesis phase fractions in LCA-positive populations were uniformly less than the corresponding cytokeratin (CK)-positive cells (mean LCA + SPF = 4.4% vs. mean CK + SPF = 15.5%) and varied from 3-11%. Proliferation among inflammatory populations did not correlate statistically with the total percent of LCA or CK-positive events, nor with the SPF in epithelial populations. However, proliferative activity of inflammatory components was greater in tumors with predominately intratumoral, vs. peritumoral, inflammatory cell distribution (4.6% vs. 3.3%, P = 0.03) and in tumors with greater numbers of large, 'transformed' lymphocytes (few = 3.25% vs. many = 6.5% LCA + SPF, P = 0.001). We conclude multiparameter flow cytometric analysis of mechanically-dissociated breast tumors is representative of tumor infiltrating lymphoid populations in breast tumors and provides a potentially useful means of studying biologically relevant tumor-host interactions.