Bcl‐2 Expression in Oral Squamous Cell Carcinoma

Abstract

Apoptosis is a genetically regulated process involved in tissue size regulation, morphogenesis, and elimination of genetically damaged cells. A pallet of genes is involved in the control of apoptosis, such as bcl-2 family whose oncogenic potential has been demonstrated in oral tumorigenesis. Different members of bcl-2 family may promote or inhibit apoptosis by synthesizing anti- and proapoptotic proteins. One of antiapoptotic proteins, bcl-2, with a crucial role in apoptosis regulation was the object of our study. By means of immunohistochemistry we estimated the level of overexpression of bcl-2 proteins in a series of the 26 formalin fixed, paraffin-embedded samples of oral squamous cell carcinoma (OSCC). Analyzed tumors originated from different sites of oral cavity; 7/26 belonged to stage II, 14/26 to stage III, and 5/26 to stage IV. Immunoreactivity was scored according to the percentage and intensity of positive cytoplasmic bcl-2 staining. All tumors had low percentage of positively stained bcl-2 cells, with mean values for lower/higher intensity of 8.3 +/- 2.5/34.4 +/- 7, 7.5 +/- 1.1/31.9 +/- 4.3, and 8.4 +/- 5.8/31.5 +/- 5.8 within stages II, III, and IV, respectively. Low level of bcl-2 expression in our sample seems to be associated with higher survival rate: 77% for the 5-year follow-up period. Comparing clinicopathologic and risk factors data within each and between three groups of analyzed tumors (lip-tongue P = 0.58, tongue-floor of the mouth, P = 0.21, lip-floor of the mouth, P = 0.50) there was no significant difference. However, our results suggest that the level of bcl-2 expression could be a valuable predictor of tumor behavior and disease outcome.

Plumbagin induces the apoptosis of human tongue carcinoma cells through the mitochondria-mediated pathway

“…The results involving the induction of apoptosis in Tca8113 cells by plumbagin are consistent with previous findings using other cancer cell lines such as human melanoma cells, cervical cancer cells, and breast cancer cells [45,46]. Bcl-2 family members are apoptosis regulatory proteins which are strongly correlated with the oncogenesis and progression of OSCC [28,47,48]. The Bcl-2 family proteins are known to regulate apoptosis by changing its relative levels.…”

“…Reduced apoptotic cancer cell number was closely related with poor prognosis of tongue carcinomas [5]. A pallet of genes are involved in the control of apoptosis such as the Bcl-2 family whose oncogenic potential has been demonstrated in oral tumorigenesis [28]. Bcl-2, a potent suppressor of apoptosis, can form a heterodimer with the apoptotic protein Bax and thereby neutralize its apoptotic effects.…”

Prognostic Implications of MicoRNA miR-195 Expression in Human Tongue Squamous Cell Carcinoma

“…In this study, the expression of the Cyclin D1 was only statistically significantly associated with the tumor size of TSCC but not with other clinicopathological factors analyzed, whereas the expression of Bcl-2 in TSCC was not statistically significantly associated with any of the clinicopathological factors analyzed. However, according to previous studies, the role of Cyclin D1 as a prognostic marker remains controversial [32], [33], [34], [35], [36], [37] and there is no consensus on the use of Bcl-2 as a prognostic marker [38], [39], [40], [41] for squamous cell carcinomas among head and neck cancer patients either. Our results concerning Cyclin D1 and Bcl-2 were consistent with some of these publications [35], [36], [37], [38], [39].…”

Expression of Bcl‐2 family proteins and association with clinicopathological characteristics of oral squamous cell carcinoma

“…One of the most studied anti‐apoptotic proteins is Bcl‐2. Its abnormal expression has been reported in a number of solid tumours such as lung, thyroid, breast, ovary, stomach and colonic carcinomas 16 …”