Introduction/Background*Previously, we and others have demonstrated that the N-acylethanolamine, anandamide, inhibits endometrial cancer (EC) cell growth in-vitro1,2. The mechanism probably involves cellular apoptosis2, through modulation of pro-apoptotic (BAX) and anti-apoptotic molecules (Bcl-2). Our aim here was to investigate the distribution patterns of these proteins and that of a cell proliferation marker in patients with and without EC.

Methodology Endometrial biopsies from patients with Type 1 (n=18), Type 2 EC (n=10) and normal atrophic endometria (n=6) were subjected to immunohistochemistry with commercial antibodies to BAX, Bcl-2 or Ki-67. Histomorphometric analyses of the glands and stroma were measured independently on 10 random fields from each sample using Imagescope software3. The mean ± SEM were calculated, and significance (p<0.05) determined using ANOVA.

Result(s)*BAX protein was significantly higher in Type 1 (p=0.004) and Type 2 (p=0.024) EC compared to atrophic samples; both types showing higher levels in the glandular tissue; only Type 1 EC demonstrated significantly higher stromal staining. By contrast, Bcl-2 expression was significantly (p=0.017) lower only in Type 2 EC. Increased proliferation (Ki-67 staining) of both Type 1 (p=0.003) and Type 2 (p<0.0001) EC was observed. The BAX:Bcl-2 ratio was only significantly (p<0.001) higher in the Type 2 EC because of glandular expression. BAX expression (r=0.615; p=0.0001), and the BAX:Bcl-2 ratio (r=0.507; p=0.003) were directly related to proliferation whilst Bcl-2 expression was inversely related (r=-0.544; p=0.0009).

Conclusion*Since BAX (pro-apoptotic signal) was increased in both types of EC, whilst Bcl-2 (anti-apoptotic signal) was decreased, then increased apoptosis is present in EC tissue. The direct correlation between the BAX:Bcl-2 ratio (indicator of increased or decreased apoptosis) and cellular proliferation indicates that as the tumours grow, they also undergo significant apoptosis. Since these tissues have increased production of anandamide4, then it is probable that anandamide is not stimulating cellular proliferation but is attempting to control tissue hyperplasia through increased apoptosis.