Immunohistochemical analysis of proliferating cell nuclear antigen and minichromosome maintenance complex component 7 in benign and malignant salivary gland tumors

Abstract

Background: Proliferation markers have been used to determine the behavior and prognosis of
benign and malignant tumors; this study was aimed to compare the immunohistochemical (IHC)
expression of proliferating cell nuclear antigen (PCNA) and novel marker minichromosome
maintenance complex component 7 (MCM7) in common salivary gland tumors including pleomorphic
adenoma (PA), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (AdCC), to find
a possible significant correlation between benign and malignant tumors.
Materials and Methods: In this cross‑sectional study, a total of 90 cases, including 30 PAs, 30 MECs,
and 30 AdCCs, were collected. The IHC expressions of PCNA and MCM7 were evaluated. Their
expressions were compared with each other and between benign and malignant tumors. Statistical
analysis was performed by Chi‑square and Tukey’s test. P value was considered 0.05.
Results: Out of 30 cases of PA, 28 cases (93.3%) were PCNA positive and 28 cases (93.3%) were
MCM7 positive. In the AdCC cases, 29 cases (96.6%) were PCNA positive and 29 cases (96.6%)
were MCM7 positive. In the MEC cases, all cases (100%) were PCNA positive and 23 cases (76.6%)
were MCM7 positive. The labeling index (LI) of MCM7 and PCNA was evaluated, and this index
was lower in MCM7 LI than PCNA in all tumors. The MCM7 and PCNA expression showed a
significant difference in PA and MEC (P < 0.001).
Conclusion: PCNA expression was higher than MCM7 expression in salivary gland tumors.
However, more studies are needed to evaluate the malignant activity of these tumors with group
of markers such as MCM family members.
Key words: Adenoid cystic carcinoma, minichromosome maintenance complex component 7,
mucoepidermoid carcinoma, pleomorphic adenoma, proliferating cell nuclear antigen