Expression of tumor antigens and heat-shock protein 70 in breast cancer cells after high-intensity focused ultrasound ablation.

BACKGROUND: Previous results have shown that high-intensity focused ultrasound (HIFU) ablation can potentially activate a host antitumor immunity. The goal of this study was to investigate whether the tumor antigens expressed on breast cancer cells may be preserved after HIFU treatment, and to explore the potential mechanisms regarding the enhanced antitumor response.
METHODS: The primary lesion in 23 patients with biopsy-proven breast cancer were treated with HIFU, then submitted to modified radical mastectomy. By using biotin-streptavidin-peroxidase immunohistochemical technology, a variety of cellular molecules expressed on breast cancer cells, including tumor antigens and heat-shock protein 70 (HSP-70), were stained in all breast specimens. A complete absence of staining was recorded as negative, and immunoreaction of the tumor cells was considered to be positive for antigen expression.
RESULTS: Nuclear positivity of breast cancer cells for proliferating cell nuclear antigen, estrogen receptor, and progesterone receptor was detected in 0%, 9%, and 9% of the treated samples, respectively. The positive rate of cytoplasmic staining for matrix metalloproteinase 9, carbohydrate antigen 15-3, vascular endothelial growth factor, transforming growth factors beta1 and beta2, interleukin 6, and interleukin 10 was 0%, 52%, 30%, 57%, 70%, 48%, and 61% in the treated cancer cells, respectively. The positive rate of cellular membrane staining for epithelial membrane antigen, CD44v6, and HSP-70 was 100%, 0%, and 100% in the zones of treated cancer cells, respectively.
CONCLUSIONS: After HIFU ablation, some tumor antigens remained in the tumor debris. This could provide a potential antigen source to stimulate antitumor immune response.