Cultured breast cystosarcoma phylloides cells and applications to patient therapy

Malignant cystosarcoma phylloides (CP) is a relatively rare cancer of the breast. A CP tumor was processed as part of a tumor acquisition, propagation, and preservation program in patient biotherapy. Two tissue culture cell lines were developed from this tumor, one directly from the biopsy, another from a xenograft tumor grown in athymic mice. The two cell lines were similar in character. There was strong immunochemical reactivity with antibodies to vimentin, type I collagen, and type III collagen. There was no reactivity with antibodies to cytokeratin and epithelial membrane antigen. Both cell lines were aneuploid, clonogenic in soft agar, and tumorigenic in nude mice. 5α-dihydrotestosterone and thyroxine added to the culture medium stimulated growth, while testosterone, 17β-estradiol, and 4-hydroxytamoxifen were without effect. Dexamethasone and cortisol were inhibitory at high doses (10−6M). Dibutyryl cyclic AMP, theophylline, and vitamin C were all inhibitory. The biopsy contained tumor-infiltrating lymphocytes which proliferated in cultures containing interleukin 2. The expanded lymphocytes were activated T cells which had the capacity to lyse tumor cells. These results suggest possibilities in the therapy of cystosarcoma phylloides involving vitamin C, certain hormones, and tumor-infiltrating lymphocytes.