Immunocytochemical analysis of breast cancer cells (A through D, immunohistochemical stain shown in red and nuclear counterstain in blue). Cytospins of cells from a breast cancer biopsy were stained with anti-LMWK (A, original magnification × 400) and anti-CD77 (B, original magnification × 400). The metastatic breast cancer cell line JS1 was grown on plastic slides and stained with anticytokeratin AE1/AE3 (C, original magnification × 400) and anti-CD77 (D).