The Effect Of Tamoxifen On Estrogen Signal System And The Expression Of Apoptosis Protein In Gastric Cancer

Objective: To study the variation of estrogen receptor, progesterone receptor (a protein product of estrogen signal system) and bcl-2 protein (a protein product of apoptosis gene) on the patients with gastric cancer who underwent the treatment of tamoxifen, and to elucidate the effect of anti-estrogen treatment on estrogen signal system and the expression of cellular apoptosis gene in gastric cancer.Method: 50 patients with gastric cancer which diagnosis was identified by gastroscopy were divided into two groups. In the treatment group (n=40), tamoxifen was given with the dose of 20mg tid x 5-7 days before operation, hi the control group (n=10), no drug was given to patients who had the similar clinical characteristic with the treatment group before operation. The expression of estrogen receptor, progesterone receptor and bcl-2 protein in the specimens from . .> roscopy and operation were measured by immunohistochemistry technique (SP method).Results: 1. Before or after the operation, the significant difference of cellular differentiation can not be found between the two groups of patients (P>0.05). 2. In the treatment group, the expression of estrogen receptor was down-regulated by tamoxifen (p<0.05). The significant difference of the expression of estrogen receptor can not be found in the control group (P>0.05). 3. In the treatment group, the expression of bcl-2 protein was down-regulated by tamoxifen (p<0.05). hi the control group, the significant difference of the expression of bcl-2 can not be found (PXX05). 4. Before or after the operation, there was no significant difference on the expression of progesterone receptors between the two groups (P>0.05). 5. Before and after the treatment of tamoxifen, the significant difference from the expression of progesterone receptor andbcl-2 protein in ER positive specimen can not be found (PX).05). Conclusions: 1. Tamoxifen can antagonise estrogen receptor in patients with gastric cancer, down-regulate the expression of estrogen receptor for the purpose of growth control in gastric cancer. 2. Tamoxifen can down-regulate the expression of bcl-2, which might happen partially though blocking the estrogen receptor, lead to the apoptosis in tumor cells to inhibit gastric cancer. 3. The effect of tamoxifen on progesterone receptor can not be identified in this study. The further research should be carried out to understand the integrity function of tamoxifen on the estrogen signal system.