Expressions Of The Autophagy-related Markers Beclin 1, LC3 And Egfr In Human Cervical Squamous Cell Carcinoma

Introduction: Cervical cancer has been considered as one of the most common causes of morbidity and mortality of gynecologic malignancies worldwide1. Histopathologically, the most common subtype of cervical cancer is squamous cell carcinoma(SCC), which accounts for up to 90% of these tumours. Poor prognostic factors for early stage cervical cancer include large tumour diameter, pelvic lymph node metastasis, parametrial invasion, positive surgical margins and deep stromal and lymphovascular invasion2. However, whether such prognostic factors are sufficiently accurate to estimate prognosis and determine therapeutic strategies remains controversial. Thus, biological characteristics of cervical cancer should be understood and novel molecular markers should be developed to accurately predict the prognosis of patients.Autophagy is a self-digesting process in which retired organelles and long-lived proteins are removed to provide a survival mechanism for cells under stress, hypoxia and starvation3,4. However, the role of autophagy in tumourigenesis is complicated, and the function of autophagy also presumably differs in different stages of cancer development. In initial stages of cancer development, autophagy may hinder proliferation of cells with cancer-linked mutations. Once a tumour develops, cancer cells can utilise autophagy for cytoprotection. Beclin1 and cytosolic microtubule-associated protein light chain 3(LC3) genes play an important role in mammalian autophagy, both of which are involved in autophagosome formation5-8.Epidermal growth factor receptor(EGFR), an oncogenic receptor tyrosine kinase, is hyperactive in various types of solid tumours. EGFR is implicated in cellular proliferation, metastasis, angiogenesis, apoptosis inhibition, chemoresistance and radioresistance. The activation of EGFR also regulates autophagy through multiple signalling pathways10.In this study, the expressions of EGFR and autophagy-related markers, namely, Beclin-1, LC3, in cervical SCC, high-grade cervical intraepithelial neoplasia(CIN) and normal cervical epithelial tissues were investigated; the prognostic significance of EGFR and Beclin1, LC3 expression in cervical SCC was also evaluated.Aims: To investigate the expression of Beclin-1, LC3 and EGFR in cervical squamous cell carcinoma(SCC), high grade cervical intraepithelial neoplasia(CIN) and normal cervical tissues and their prognostic significance.Methods: Immunohistochemistry was performed to analyze the Beclin 1, LC3 and EGFR expressions in 80 cancer tissues, 40 high grade CIN tissues and 40 normal cervical tissues. χ2and Fisher’s exact tests were used to compare different protein expression rates. The Kaplan-Meier method and log-rank test was used to determine the difference of OS rates.Results: Beclin 1 immunoreactivity was positively expressed in cervical cancer cells, high-grade CIN cells and normal cervical epithelial cells of 26.2%(21/80), 77.5%(31/40) and 82.5%(33/40) of patients, respectively. LC3 was positively expressed in 28.8%(23/80), 70.0%(28/40) and 75.0%(30/40) of cervical cancer, high-grade CIN and normal cervical tissues, respectively. The positive expression rate of Beclin 1 and LC3 was significantly decreased in cervical cancer tissues compared with that in high-grade CIN and normal cervical tissues(p=0.000). EGFR was positively expressed in 68.8%(55/80), 62.5%(25/40) and 12.5%(5/40) of cervical cancer tissues, high-grade CIN and normal cervical tissues, respectively. The positive expression rate of EGFR was significantly decreased in normal cervical tissues compared with that in cervical cancer and high-grade CIN tissues(p=0.000). The negative expressions of Beclin1 or LC3 in cervical SCC with positively expressed EGFR promoted high FIGO stage and lymph node metastasis than those in other cells(p = 0.011;p = 0.036 or p = 0.013; p = 0.092). Five-year OS rates did not significantly differ between patients with negatively and positively expressed Beclin 1, LC3 or EGFR(p > 0.05). The five-year OS rates of EGFR-positive patients with negatively expressed Beclin1 or LC3 decreased compared with those of EGFR-positive patients with positively expressed Beclin1 or LC3. Nevertheless, five-year OS rates did not significantly differ between the two groups(p > 0.05).Conclusions: Autophagy was down-regulated in cervical SCC. The down-regulation of autophagy combined with the up-regulation of EGFR may promote a higher FIGO stage and lymph node metastasis.