MKI67 and neoplasm: All three markers were consistently modulated in progressive tumor stages, indicating in particular: i) an increase in cell proliferation, with highest enrichment of Ki67-positive cells at stage 6 (50.9%, versus 9% in normal breast and 18.2% in stage 1); ii) decreasing ER expression, virtually disappearing at stage 5 (only rare scattered cells with weak signals are visible at stage 6), and iii) increased ERB2 expression, peaking at stage 5.