Correlation of ER with Bcl-2 in cervical cancer and pre-cancerous lesion

Objective: This study aimed to investigate the relationship between estrogen receptor (ER) and Bcl-2 in cervical cancer and precancerous lesions. Methods: ER and Bcl-2 were evaluated by immunohistochemistry in 20 non-tumor tissues, 30 low-grade cervical intraepithelial neoplasias, 70 high-grade cervical intraepithelial neoplasias, and 80 cervical cancers. Results: The positive rate of ER was 75% in non-tumor tissues; this rate decreased with disease severity (χ2=24.266, P<0.01). The overexpression of ER protein was remarkably lower in cervical intraepithelial neoplasias (CIN) II-III and carcinomas than in non-tumorous cervices. Differences were not significant between CIN I and non-tumorous cervices (χ2=0.751, P=0.386). Furthermore, ER expression was not correlated with histological type and tumor grade. The positive rate of Bcl-2 was 75.38% in squamous cell carcinoma. This rate increased with disease severity (χ2=27.715, P<0.01). The Bcl-2 protein overexpression was remarkably higher in CIN I, CIN II-III, and carcinomas than in non-tumorous cervices. Bcl-2 expression was also not correlated with histological type (P=0.500); by comparison, Bcl-2 expression was correlated with tumor pathological grade (χ2=4. 862, P=0.027). The co-expression of ER and Bcl-2 was 38.57% and 15.38% in CIN II-III and squamous cell carcinoma, respectively; the differences between these two values were significant (χ2=9.108, P=0.003). A correlation between ER and Bcl-2 was observed in CIN II-III (r=0.506, P<0.01); no correlation was observed between other groups. Conclusion: ER expression was inversely correlated with Bcl-2 in cervical cancer progression. The co-expression of these markers may have an important function in the course of high-grade cervical intraepithelial neoplasia.