Background: This study seeks to determine the relationships between manifestation of myofibroblasts in the stroma tissue of hyperplastic pre-invasive breast lesions to invasive cancer by investigating clinicopathological data of patients, their effect on steroid receptor expression and HER2, and angiogenesis according to CD34 antigen expression.
Methods: 100 cases of invasive ductal carcinoma were immunohistochemically investigated for the presence of smooth muscle actin (SMA), ER/PR, HER2, anti-CD34 antibody and microvessel count (MVC). Patients were scored in four different zones of invasive areas: invasive cancer, DCIS, fibrocystic disease ± ductal intraepithelial neoplasia (FCD ± DIN), and normal tissue.
Results: There was a significant difference in stromal myofibroblasts between all areas except for the stroma of DCIS and FCD ± DIN (P < 0.001). We observed positive significant correlations between stromal myofibroblasts, HER2 expression, and the numbers of involved lymph nodes in invasive cancer, DCIS, and FCD ± DIN (P < 0.001). More myofibroblasts were present in grade III cases, with the least frequent observed among grade I cases in the stroma of those with invasive disease, DCIS, and FCD ± DIN (P < 0.001). MVC was inversely related to stromal myofibroblasts in invasive cancer (P < 0.001) and DCIS (P < 0.001), whereas there was a positive correlation in the stroma of FCD ± DIN (P = 0.002) and normal areas (P = 0.054). There was a significant difference in MVC observed in all areas except for DCIS and FCD ± DIN (P < 0.001). We noted significant inverse correlations between MVC, HER2 expression, and the numbers of involved lymph nodes in invasive cancer and DCIS (P < 0.001). Most MVC were present in grade I, with the least frequent observed in grade III cases in the stroma of invasive cancer, DCIS and FCD ± DIN (P < 0.001).
Conclusion: Angiogenesis can be observed before any significant myofibroblastic changes in the pre-invasive breast lesions. The elevated content of myofibroblasts in stroma of tumor; probably may be a worse prognostic factor and the steps from atypical epithelial hyperplasia to DCIS and then to the invasive carcinoma do not appear to be always part of a linear progression.