Endogenous versus tumor-specific host response to breast carcinoma: a study of stromal response in synchronous breast primaries and biopsy site changes.

PURPOSE We recently described two types of stromal response in breast cancer derived from gene expression studies of tenosynovial giant cell tumors and fibromatosis. The purpose of this study is to elucidate the basis of this stromal response--whether they are elicited by individual tumors or whether they represent an endogenous host reaction produced by the patient. EXPERIMENTAL DESIGN Stromal signatures from patients with synchronous dual primaries were analyzed by immunohistochemistry on a tissue microarray (n = 26 pairs) to evaluate the similarity of stromal responses in different tumors within the same patient. We also characterized the extent to which the stromal signatures were conserved between stromal response to injury compared to the stromal response to carcinoma using gene expression profiling and tissue microarray immunohistochemistry. RESULTS The two stromal response signatures showed divergent associations in synchronous primaries: the DTF fibroblast response is more likely to be similar in a patient with multiple breast primaries (permutation analysis P = 0.0027), whereas CSF1 macrophage response shows no significant concordance in separate tumors within a given patient. The DTF fibroblast signature showed more concordance across normal, cancer, and biopsy site samples from within a patient, than across normal, cancer, and biopsy site samples from a random group of patients, whereas the CSF1 macrophage response did not. CONCLUSIONS The results suggest that the DTF fibroblast response is host-specific, whereas the CSF1 response may be tumor-elicited. Our findings provide further insight into stromal response and may facilitate the development of therapeutic strategies to target particular stromal subtypes.