Epithelial-mesenchymal transition inducer Snail1 and invasive potential of intraductal breast cancer

Background and Objectives: Transcription factor Snail1 is a key inducer of epithelial-mesenchymal transition (EMT), a biological process implicated in the cancer progression and metastasis. The aim of the study was to investigate Snail1 expression in DCIS found on breast biopsy and assess its predictive value for the final invasion. Methods: A total of 209 patients with histologically diagnosed pure DCIS entered the study. Snail1 reactivity was evaluated with immunohistochemistry in tumor tissue from stereotactic vacuum-assisted biopsy of suspicious microcalcifications. Results: Snail1 staining was observed in 62% of tumors: weak, intermediate, and strong in 27%, 21%, and 14% of lesions, respectively. Positive Snail1 expression was significantly rarer in DCIS presenting as powdery microcalcifications, when compared with crushed stone-like and casting-type and was more common in DCIS with comedonecrosis. Correlation with other features was not significant. None of standard parameters significantly influenced the upgrading rate. In contrast, in uni- and multivariate analysis the risk of postoperative invasion was significantly associated with positive Snail1 immunoreactivity. Moreover, there was a significant stepwise increase of upgrading rate according to Snail1 expression in DCIS cells: weak 9%, intermediate 26%, and strong 55%, respectively. Conclusions: Snail1 can reflect the invasive potential of DCIS and help identify its more aggressive subtypes.