Patients With Invasive Ductal Carcinoma Have Reduced Levels of Decorin Expression in Their Breast Tissue Compared to Patients With Fibroadenoma While Plasma Decorin Remains Unchanged

Reduction in the level of tissue decorin is a hallmark of many types of cancer including breast carcinoma. However, reduced decorin expression has also been reported in several types of benign tumors to the extent that it has been proposed as a tissue marker to differentiate malignant from benign tumors. The aim of this study was to investigate the potential role of plasma decorin to distinguish breast cancer from fibroadenoma, the second most common type of benign tumor, after fibrocystic disease. From 35 patients recruited in this study, 24 were affected with invasive ductal carcinoma, either grade II (n = 14) or grade III (n = 10). The other 11 patients had fibroadenoma lesions in their breasts. Tissue decorin mRNA and protein levels were assessed with real-time qPCR and Immunohistochemical analysis. ELISA was employed to measure plasma levels of decorin. The mean plasma decorin in cancer patients was measured to be 5.42 ± 1.83 ng/mL while fibroadenoma patients had an average of 4.22 ± 1.17 ng/mL decorin in their plasma. The difference was not significant. However, the mean expression level of decorin mRNA calculated by the 2-ΔΔCt method was 5.6-fold lower in the biopsied tissue specimens of IDC patients versus fibroadenoma, as expected. Consistent reduction in protein abundance was observed in the studied tissue sections. We have shown that tissue decorin is a reliable marker, unaffected by patient disease stage, to differentiate IDC from fibroadenoma. However, plasma decorin does not seem to have diagnostic value in this regard.