Expression and prognostic significance of Bcl-2 in ovarian tumours

Abstract

Summary The expression of bcl-2 was studied in normal ovanres and in ovarian tumours by immunohistochemical analysis. Normal epithelium was strongly stained in all nine examined ovaries. In comparison. all tumour groups showed a substantially decreased tumour cell expression of the same order of magnitude. Thus. benign tumour cells were weakly stained in two and unstained in two samples, while the remaining eight showed strong expression. Of ten borderline samples. one was unstained and five had weakly and four strongly bcl-2 positive tumour cells. Finally. 24 of 50 malignant tumours showed strong staining, while weak or no expression in tumour cells was found in 16 and 10 samples respectively. The reduced staining deviated significantly from normal ovary for both borderline (P = 0.02) and malignant groups (P = 0.01). Tumour cell staining with the bcl-2 antibody was significantly reduced when tumour mass had to be left behind compared with those with no visible remaining tumour (P = 0.03 and 0.003 for weakly and strongly stained tumours respectively). The expression of bcl-2 in malignant tumour cells was inversely correlated with the expression of p53. Bcl-2 expression was correlated with survival with significantly reduced survival in weakly (P = 0.02) and unstained (P<0.001) groups compared with those patients having strongly stained malignant tumour cells. This correlation between the presence of bcl-2 and survival was maintained in the subgroups of patients with advanced disease or with residual tumour bulk and was also the case in patients having p53-positive tumours. Our results indicate an inhibitory role of bcl-2 in development and progression of ovarian tumours.

Reduced expression of BAX is associated with poor prognosis in patients with epithelial ovarian cancer: a multifactorial analysis of TP53, p21, BAX and BCL-2

“…This is consistent with findings from several other studies (Baekelandt et al, 1999a(Baekelandt et al, , 1999bDiebold et al, 1996;Herod et al, 1996;Marone et al, 1998) although an inverse correlation between TP53 and BCL-2 (Henriksen et al, 1995) and between TP53 and p21 (Anttila et al, 1999) has also been reported in ovarian tumour tissues. The lack of a correlation between TP53 and its downstream genes may reflect the fact that expression of these genes is also regulated by TP53-independent pathways.…”

“…However, patients with increased BCL-2 expression tended to have a better progression-free and overall survival compared to patients with low BCL-2 expression in their tumours. Several studies have correlated BCL-2 with a survival advantage in ovarian cancer (Baekelandt et al, 1999b;Diebold et al, 1996;Henriksen et al, 1995;Herod et al, 1996) but failed to find an association with overall response to chemotherapy (Baekelandt et al, 1999b;Herod et al, 1996). In contrast, BCL-2 expression has also been reported to be associated with a poor prognosis and resistance to chemotherapy (Kassim et al, 1999;Mano et al, 1999).…”

Telomerase activity and p53-dependent apoptosis in ovarian cancer cells

“…Bcl-xL, which is one of the Bcl-2 family, has an important role in solid tumours, (Marone et al, 1998). Bcl-xL, a functional and structural homologue of Bcl-2, provides protection from apoptosis (Boise et al, 1993;Henriksen et al, 1995;Marone et al, 1998). In the present study, the expression of Bcl-xL decreased after exposure to CDDP in all cell lines.…”

Comparison of clinical staging of benign and malignant ovarian tissues with DNA flow cytometry

“…Also, proliferative rate [9,12,15,[17][18][19][20][21][22][23][24] , growth factors and their receptors [25] , lamina receptors [26] and functional and structural alterations of oncogenes and oncosuppressor genes [21,22,[25][26][27][28][29] have been studied. Biomarkers directly involved in drug resistance, such as proteins associated with multidrug resistance detoxification [30][31][32][33][34][35][36] , have also been determined as indicators of clinical outcome.…”