Abstract
Background: Gene expression profiling of breast cancer has demonstrated the importance of stromal response in determining the
prognosis of invasive breast cancer. The host response to breast cancer is of increasing interest to pathologists and may be a future
focus for novel pharmacological treatments.
Methods: This study describes the pattern of distribution of stromal myofibroblasts using immunostains for CD10 and smooth
muscle actin (SMA) in 50 primary breast cancers and their matched nodal metastases (68.6% nodes positive and 31.4% nodes
negative). The stroma within the tumor (intratumoral) and at the advancing tumor edge (peri-tumoral) was studied in both primary
and nodal sites. A simple quantitative scoring system was employed for both immunostains. The correlation between expression
of these markers by stromal cells and standard pathological prognostic factors of stage, grade, hormone receptor and Her-2 status
was analysed.
Results: SMA-positive stromal cells were more abundant in peri-tumoral stroma compared with intratumoral stroma in both
primary and metastatic lesions. SMA expression in the lymph node metastases showed a significant correlation with tumor stage.
SMA expression in peri-tumoral stroma correlated with Her-2 status.
Conclusion: The results of this study suggest that myofibroblasts, particularly those expressing SMA, might potentiate the
progression of the carcinomatous process especially in nodal metastases. Thus these cells may be a potential therapeutic target.