Ki‐67 As a Prognostic Marker in Adenoid Cystic Carcinoma Assessed With the Monoclonal Antibody MIB1 in Paraffin Sections

The monoclonal antibody MIB1 recognizing the Ki-67 antigen in formalin-fixed, paraffin-embedded tissue was used to study the proliferative activity in 44 adenoid cystic carcinomas of the salivary glands. The antigen expression was compared with clinical factors, histopathological grading, and prognosis. The Ki-67 value was significantly higher in tumors from patients suffering from treatment failure than in nonfailures (P < 0.001). The Ki-67 expression was also higher in tumors exhibiting areas more than 30% of the solid growth pattern and higher in sinonasal tumors than in other locations. By Cox regression analysis, Ki-67 more than 4% was the strongest prognostic indicator (P <0.005). Clinical stage and violation of surgical margins were also found to be independent significant prognostic indicators. We conclude that Ki-67 expression estimated by the use of MIB1 is a powerful tool for predicting the short-term prognosis for patients with adenoid cystic carcinoma.