Analysis of the expression of hyaluronan in intraductal and invasive carcinomas of the breast

To evaluate hyaluronan expression at different stages of tumoral progression in primary breast cancer. Hyaluronan expression was evaluated by histochemical techniques in 42 cases of pure DCIS, in 15 cases of DCIS with a microinvasive component, and in 32 cases of invasive ductal carcinoma of the breast. Staining results were evaluated by calculating the percentage of stained areas by means of a specific software program. Our results show higher values of hyaluronan expression in invasive breast carcinomas [median of percentage of stained areas 41.1 (range 8-69.2)] and in DCIS with a microinvasive component [48.6 (16.8-62.8)] than in pure DCIS [14.5 (1-44.4)] (p < 0.001, for both). Our study indicates a proportionally higher area of hyaluronan expression in DCIS with a microinvasive component than in pure DCIS, suggesting a key role of this glycosaminoglycan in the early invasive phase of breast carcinomas. Thus, hyaluronan could play an important function in determining the migratory phenotype of cancer cells. Larger size tumors appear to demonstrate an intricate balance between hyaluronan synthesis and degradation, thus conditioning intratumoral heterogeneity in the hyaluronan metabolism.