Introduction: Salivary gland tumors (SGTs) may represent a considerable diagnostic challenge, primarily because of the complexity of the
classification and the rarity of several entities. Since proliferative activity is a reliable method to assess tumor biology. There has been continuous
research to find such biological markers. Ki-67 is a widely accepted proliferation marker, with its expression tightly associated with the cell cycle. It
is implicated in many of human cancers as a prognostic factor. MCM-3, member of minichromosome maintenance proteins family, is upregulated
in proliferating cells. MCM-3 overexpression in almost all human cancers implicates that it might facilitate the tumorigenesis by
playing a role in the malignant transformation of cells.
Objectives: to evaluate the MCM-3 protein expression in benign and malignant salivary gland tumors and compare the obtained results with the
expression of Ki-67 proliferation antigen.
Materials and methods: Immunohistochemical analysis of 20 cases of SGTs with 2 sections from each specimen (20 sections for antiKi-
67antibody and 20 sections for antiMCM3antibody) and 5 control cases. Immunohistochemical staining was performed using a Labeled Strept-
Avidin Biotin method (LSAB).
Results: Normal salivary gland tissue showed negative immunoreactivity for both Ki-67 and MCM-3 in epithelial and myoepithelial cells. All the
examined cases showed positive expression for both proliferative markers in benign and malignant SGTs, with different intensities.
Conclusions: The proliferative markers Ki-67 and MCM-3 proteins are overexpressed in malignant salivary gland tumors, than benign ones.
Both Ki-67 and MCM-3 may be reliably applied as diagnostic markers to distinguish benign from malignant salivary gland tumors.