Lumican mRNA has been identified as being differentially expressed between different regions of the same human breast tumor. In situ hybridization study of 26 independent breast tumors confirmed the presence of lumican mRNA in fibroblast-like cells within stroma and showed a significant increase of its expression in tumor compared to adjacent normal stroma (P < 0.001). Higher lumican expression was associated with higher tumor grade, lower estrogen receptor levels in the tumor, and younger age of the patients (P < 0.05). Reverse transcription-PCR analysis of total RNA extracted from 19 independent breast tissues exhibiting lesions that are thought to parallel tumor progression also suggests that this proteoglycan is differentially expressed during tumor progression.
This work was supported by grants from the Canadian Breast Cancer Research Initiative (CBCRI) and the United States Army Medical Research and Materiel Command (USAMRMC). The Manitoba Breast Tumor Bank is supported by funding from the National Cancer Institute of Canada (NCIC). P. H. W. is a Medical Research Council of Canada (MRC) Clinician Scientist, and L. C. M. is a MRC Scientist. E. L. is a recipient of a USAMRMC Postdoctoral Fellowship.