Antigens, Neoplasm/immunology; B-Lymphocyte Subsets/immunology; Breast Neoplasms/immunology; Carcinoma, Medullary/immunology; Gangliosides/chemistry; Gangliosides/immunology; Lymphocytes, Tumor-Infiltrating/immunology; Animals; Antigens, Neoplasm/metabolism; B-Lymphocyte Subsets/pathology; Binding Sites, Antibody/genetics; Breast Neoplasms/chemistry; Breast Neoplasms/pathology; COS Cells; Carcinoma, Ductal, Breast/chemistry; Carcinoma, Ductal, Breast/immunology; Carcinoma, Ductal, Breast/pathology; Carcinoma, Medullary/chemistry; Carcinoma, Medullary/pathology; Cell Line; Cell Line, Tumor; Clone Cells; DNA Mutational Analysis; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Gene Rearrangement, B-Lymphocyte, Heavy Chain; Gene Rearrangement, B-Lymphocyte, Light Chain; Humans; Immunoglobulin Fab Fragments/chemistry; Immunoglobulin Fab Fragments/genetics; Immunoglobulin Joining Region/genetics; Immunoglobulin Joining Region/isolation & purification; Immunoglobulin Variable Region/genetics; Immunoglobulin Variable Region/isolation & purification; Immunoglobulin lambda-Chains/genetics; Immunoglobulin lambda-Chains/isolation & purification; Lymphocytes, Tumor-Infiltrating/pathology; Neoplasm Invasiveness; Peptide Library; Sequence Analysis, DNA