Bax and Bak expression in cervical smears of women with low-and high-risk HPV types: A study of 120 cases

Abstract

Background:Human papillomavirus (HPV) is known to be involved in the carcinogenesis of squamous cells in uterine cervix cancer, mostly by binding and inactivating the p53 and pRb tumor suppressor genes. Lately, evidence has emerged suggesting that HPV oncoproteins may interact with proteins involved in cellular apoptosis as well.Aim:This study aimed to investigate the expression of proapoptotic proteins Bax and Bak in women with low-risk and high-risk HPV types as opposed to HPV-negative women, and in women with normal pap smear compared to women with abnormal Papanicolau test (Pap) smear.Materials and Methods:A total of 120 liquid-based cervical samples were subtyped for HPV types with microarray hybridization and then stained and evaluated immunocytochemically for Bax and Bak expression. Statistical analysis was performed on the Bax and Bak scores (percentage of positive cells × staining intensity), the overall percentage of positive cells, and the most prevalent staining intensity group found in each sample.Results:A weak association between negative Bax staining and cytologically normal Pap smears was discovered, whereas cytologically abnormal samples tended to stain weakly or moderately positive. No other statistically significant difference was found in the other analyzed parameters.Conclusion:Cytologically normal pap smears seem to have a slight tendency to stain negative for Bax as opposed to cytologically abnormal pap smears. Although the association is weak, it is an indication that there might be a connection between the expression of Bax and the development of cervical intraepithelial dysplasia, which warrants further investigation in larger-scale studies.

<p>Progress in immunocytochemical staining for cervical cancer screening</p>

“…In 2015, an Indian group performed the HPV test, cytology test, and Bax/Bak staining in 120 specimens of cervical liquid-based cytology samples and found that Bax/Bak staining was only weakly correlated with cytological results, although these negative results may be attributable to the small sample size. Moreover, in all cases, the results showed that there is no statistically significant difference in the Bax and Bak scores between any compared groups including the control, low-risk HPV types, and high-risk HPV types group 51. Therefore, the Bax/Bak may not be considered as an accurate immunocytochemistry biomarker for cervical cancer screening according to the existing data.…”

MicroRNA-466c-3p exerts protective effect on neuronal apoptosis and improves functional recovery post spinal cord injury via mitochondrial apoptotic pathway

“…The pro-apoptotic proteins Bax and Bcl-2 can cause liberation of cytochrome C (Liu et al 2008;Noguchi et al 1999). In apoptosis process, overexpression of Bcl-2 can enhance the process by blocking Bax (Klapsinou et al 2015). Death receptor apoptosis and mitochondrial apoptosis are the two important apoptosis pathways (Su et al 2016;Lu et al 2017a, b).…”

miR-142-3p suppresses apoptosis in spinal cord-injured rats

“…In the process of apoptosis, the overexpression of Bax may encourage apoptosis via blocking Bcl-2, which is an antiapoptotic protein [ 30 ]. It had been reported earlier that both the death receptor and the mitochondrial apoptosis pathway (MAP) are the important pathways [ 31 , 32 ]. Bax is an important regulator in the MAP, and the molecule is able to build up homodimers on the mitochondrial membranes and lead to the opening of permeability pores on it for releasing CYT- C from the mitochondria in the cytoplasm [ 33 ].…”

“…In the process of apoptosis, the overexpression of Bax may encourage apoptosis via blocking Bcl-2, which is an antiapoptotic protein [30]. It had been reported earlier that both the death receptor and the mitochondrial apoptosis pathway (MAP) are the important pathways [31,32].…”