Estrogen receptor genotype is associated with platelet inhibition after tamoxifen treatment

Abstract

Backgroud Tamoxifen therapy can cause a ~ 4% decrease in platelet count. We hypothesized that this decrease may lead to changes in platelet function, and that estrogen receptor (ESR) genotype may influence tamoxifen-induced changes in platelet function. METHODS Platelet aggregation tests were performed on blood drawn from 19 women before and after 4 months of tamoxifen treatment. ESR1 PvuII and XbaI and ESR2-02 genotypes were also determined. Differences in platelet aggregation were tested using student’s t test (SPSS, v12). Data expressed as mean ± SD. RESULTS Tamoxifen therapy led to a significant decrease in ADP (13.3±3.4 vs 11.5±2.0, P = 0.012) and collagen (15.0±5.7 vs 12.2±6.1, P=0.04) induced platelet aggregation. ESR1 PvuII genotype was associated with differences in baseline ADP-induced platelet aggregation and the change in ADP-induced platelet aggregation (table 1). CONCLUSION Platelet aggregation was inhibited after 4 months of tamoxifen treatment. ESR1 PvuII genotype was associated with changes in platelet aggregation after tamoxifen treatment. Table 1.. ADP-induced Platelet aggregation based on ESR1 PvuII genotype