Contrary to in the breast cancer alone groups, in the breast cancer with PD groups, the HR status (P = 0.182 in PD-IDC and P = 0.371 in PD-DCIS), HER2 status (P = 0.788 in PD-IDC and P = 0.643 in PD-DCIS), and combined molecular subtype (P = 0.196 in PD-IDC and P = 0.853 in PD-DCIS) were not found to affect disease prognosis.
Ten patients (42%) had skin changes from ductal carcinoma in situ involving nipple skin (Paget disease), with small foci of invasion into the dermis, and 6 of those 10 carcinomas (60%) stained positive for human epidermal growth factor receptor 2 (HER2).
These cells show immunoreactivity for CKs 7, 8 and 18 but are negative for c-erbB-2/HER2, CEA and HPV-DNA and should not lead to the mistaken diagnosis of Paget's disease.
Overexpression of the neu-protein, evidenced as membrane staining by immunohistochemistry, is detected in approximately 20% of invasive duct cell carcinomas, in approximately 50% of in situ duct cell carcinomas, and in almost 100% of cases of Paget's disease.