Comparison of the expression of E-cadherin in the healthy oral mucosa, leukoplakia and oral squamous cell carcinoma: a systematic literature review

Abstract

Introduction Oral squamous cell carcinoma (OSCC) is the most frequent malignancy in oral cavity [1]. Most OSCC cases can develop from premalignant lesions, such as leukoplakia, associated with noticeable clinical and histological changes in oral mucosa [2]. Neoplastic cells undergo a dedifferentiation process, which is followed by a loss of intercellular adhesion [3]. E‑cadherin is a glycoprotein, which is an important cell adhesion molecule and signals transduction factor [1]. Its loss of expression has been noted with poorly differentiated morphology in a large number of malignancies [4]. But it remains unclear if E‑cadherin could be used as a reliable biomarker to predict malignant processes. Aim This study aims to compare the expression of E-cadherin in healthy oral mucosa, leukoplakia and oral cancer to determine the potential for malignancy. Methods A systematic search was conducted in three electronic databases, including Pubmed, WileyOnline and ScienceDirect between December 5, 2022 and December 20, 2022. The protocol of the study was conducted in line with the PRISMA statement. Following mesh terms were used: „oral cancer“, „leukoplakia“, „immunohistochemical markers”. According to the PICO schema, the study included healthy adult patients or patients diagnosed with leukoplakia or oral squamous cell carcinoma (OSCC) (P), in which immunohistochemical expression of E-cadherin was investigated (I) in different lesions (C) in order to evaluate the malignant potential of lesions(O). The criteria for the study inclusion were full-text studies published in English, clinical studies with humans and studies not older than 10 years. Results In total, 848 articles were initially identified in the electronic databases. Following the primary screening of 156 articles of titles and abstracts, 108 studies were excluded. After the final screening of 48 full texts, 6 studies were included in the final evaluation, which compares the expression of E-cadherin in epithelial cells between healthy oral mucosa, leukoplakia and OSCC[1-6].E-cadherin staining was greater in the healthy mucosa (51%), and alcohol/tobacco (51%) groups compared to leukoplakia (41%), and oral squamous cell carcinoma (38%) groups [6]. E-cadherin immunoexpression showed a statistically significant gradual decrease in the healthy oral mucosa, leukoplakia (mild and severe), and OSCC groups (p<0.05) [1-5]. The group with healthy oral mucosa had a higher percentage of E-cadherin (75-100%) than low risk and high-risk leukoplakia, which showed results from 51 to 100% and from 1 to 75%, respectively. The most significant decrease in E-cadherin expression was identified in OSCC (0-50%) [2,5]. Conclusions Study cases have shown a significant gradual decrease in E‑cadherin expression evaluating from healthy mucosa, leukoplakia (dysplasia) to oral squamous cell carcinoma, suggesting that the decrease in expression of E‑cadherin is closely related to the malignancy processes and its markedly diminished in OSCC tumors.