Bax expression has prognostic significance that is enhanced when combined with AgNOR counts in glottic carcinomas

Abstract

Recently. a family of genes whose encoded proteins share amino acid sequence homology with Bcl-2 have been identified. This family of proteins include Bcl-2. Bcl-x and Mcl-l. which act as blockers of apoptosis. whereas others such as Bax and Bak appear to promote apoptosis (Oltvai. 1993: Boise et al. 1995. The biological mechanisms by which the Bcl-2 gene family regulate apoptosis remain uncertain. The Bax protein seems. however. to act as a central regulator within this multigene family. Several studies have demonstrated that increased Bax expression is associated with increased radio-and chemosensitivity to induction of apoptosis (Bargou et al. 1996: Chresta et al. 1996: Kitada et al. 1996: Sakakura et al. 1996: Stoetzer et al. 1996: Thomas et al. 1996: Wagener et al. 1996. Information regarding the prognostic significance of Bax in human tumours is scarce. It has, however, been shown that reduced Bax expression correlates with tumour progression and shortened sunrival in breast adenocarcinomas (Krajewski et al. 1995).Moreover. it has been demonstrated that the bcl-2/bax mRNA expression ratio represents a prognostic marker in low-grade urinary

The prognostic value of spontaneous apoptosis, Bax, Bcl-2, and p53 in oral squamous cell carcinoma of the tongue

“…This observation concurs with the results of our previous study of glottic SCC. 19 Our study further revealed that high expression of Bcl-2 was significantly associated with poor prognosis and low expression with good prognosis. Previous studies of Bcl-2 expression in head and neck carcinomas have shown that both positive and negative tumors have been associated with good prognosis.…”

“…14,16 The opposite correlation was found in prostate and testicular carcinomas, 33,34 whereas no such correlation was demonstrated in colorectal carcinomas. 35 Overexpression of the Bax protein has been associated with favorable outcome in breast adenocarcinoma and glottic SCC 18,19 and poor prognosis in ovarian carcinomas, 20 whereas no association between Bax expression and prognosis was found in a study of gastric carcinomas. 36 The contradictory results concerning prognosis and expression of Bax and Bcl-2 proteins, for tumors of the head and neck as well as tumors at other sites, indicate that induction of apoptosis by proteins of the bcl-2 gene family is very complex and that the influence of individual proteins may vary from tumor to tumor.…”

“…We classified the intensity according to the dominant intensity, having examined the whole tumor area available in each section. 19 Occasional disagreements regarding the classification were discussed and a consensus reached.…”

“…19 In brief, the sections were deparaffinized by 2 washes in xylene for 5 minutes each and then dehydrated in absolute ethanol. The sections were incubated in 3% (volume of solute per volume of solvent) hydrogen peroxide in methanol (45 seconds) to block endogenous peroxidase, followed by incubation with 95% and 70% ethanol (15 seconds each), distilled water (1 minute), and phosphate-buffered saline (PBS) (5 minutes).…”

Prognostische Bedeutung der Expression von p53, bcl-2 und bax im Plattenepithelkarzinom des Larynx - Eine multivariate Analyse

“…Der Vorhersagewert von bax wurde bei Kopf-Hals-Karzinomen bislang kaum untersucht.Aufgrund der apoptosefördernden Eigenschaften des Proteins sollte seine Expression eine eher günstige prognostische Bedeutung besitzen [14,35]. Die Daten der vorliegenden Arbeit lassen einen derartigen Zusammenhang nicht erkennen.…”