Abstract: | Objective To determine the prognostic significance of MIB1 proliferation marker expression on ductal carci noma in situ (DCIS) and invasive ductal carcinoma (IDC) of the breast. Methods By means of histological and immunohis tochemical techniques, MIB1 labelling index (LI) was determined in 31 pathologic specimens (DICS 6, IDC 22 and 3 benign breast lesions as control). Results Significantly higher (P<0.05) MIB1 expression was noted in breast carcinomas in con trast with benign breast lesions. MIB1 LI increased with increasing tumor invasion from DCIS to IDC (P<0.05). Increased tendency of MIB1 LI had been also noted in according with the increased nuclear grading (NG) of IDC. Conclusion MIB1 ex pression can faithfully reflect the proliferative activity of the breast lesions, where the breast cancers with both high MIB1 LI and NG seem to have a poor prognosis. |