Phyllodes tumours of the breast: the role of CD34, vascular endothelial growth factor and ß-catenin in histological grading and clinical outcome.

AIMS: The grading and prognostication of breast phyllodes tumours remain challenging, and the value of biological markers continues to be elusive. The aim of this study was to evaluate CD34, vascular endothelial growth factor (VEGF) and ß-catenin in a series of 185 breast phyllodes tumours comprising 120 benign, 48 borderline and 17 malignant lesions. METHODS AND RESULTS: Immunohistochemistry on tissue microarrays of phyllodes tumours was performed. CD34, VEGF and ß-catenin in stromal cells were expressed, respectively, in: 38.3%, 29.2% and 27.5% of benign phyllodes tumours; 33.3%, 58.3% and 54.2% of borderline phyllodes tumours; and 5.9%, 64.7% and 76.5% of malignant phyllodes tumours; these associations with histological grade were statistically significant. There was a statistically significant inverse association of CD34 stromal expression with adverse histological features, and a positive correlation of VEGF and cytoplasmic ß-catenin stromal staining with unfavourable microscopic parameters. At a median follow-up duration of 42 months, 11 women suffered recurrences, with three succumbing from phyllodes tumour. Patients whose tumours expressed VEGF had poorer overall survival (P = 0.033), and there was a trend for worse overall survival in patients with tumour ß-catenin cytoplasmic expression. CONCLUSIONS: CD34, VEGF and ß-catenin play biological roles in breast phyllodes tumours, and may provide insights into tumour progression, with differential expression accompanying higher grades.