Cathepsin D in host stromal cells is associated with more highly vascular and aggressive invasive breast carcinoma

Aims To determinate the relationship between tumoral angiogenesis and cathepsin D (CD) expression in tumour and host stromal cells of invasive breast carcinoma, and to examine its association with classical prognostic factors such as lymph node status, histological grade, tumour size, mitotic rate, peritumoral lymphovascular invasion and oestrogen receptor (ER) status. Methods and results Sections from 102 invasive breast carcinoma were cut from the archival formalin‐fixed, paraffin‐embedded tissue blocks and stained using immunohistochemistry for the endothelial cell adhesion molecule (CD31) and CD. Microvessel density was assessed by counting vessels in the three most vascular areas at × 400 field. The counts were expressed as the highest counts within any × 400 field. The evaluation of immunostaining for CD was performed separately in both the parenchymal and stromal cells. Microvessel density was correlated positively with histological grade and peritumoral lymphovascular invasion, and correlated inversely with ER status. Positive CD staining of tumour cells was more frequent in positive ER tumours and was not significantly associated with the other classical prognostic factors. However, moderate to strong staining of host cells was correlated with higher histological grade, higher mitotic index and lack of ER protein. There was a statistically significant association between CD expression of host stromal cells and higher vessel count. Conclusions CD in host stromal cells is associated with more aggressive tumours and with a higher intratumoral microvessel density. Evaluation of CD in combination with angiogenic activity may be of some help in more accurately predicting the biological behaviour of breast carcinoma.