Genetic Study of CYP2D6 Enzyme and Therapeutic Drug Monitoring of Tamoxifen

Aim of work: 1. To estimate the frequency of Cyp2D6\*1 and \*4 alleles in Egyptian patients maintained on tamoxifen (20 mg/day) for management of ER +ve breast cancer. 2. To measure levels of tamoxifen, 4-hydroxy tamoxifen, N-desmethyl-tamoxifen and 4- hydroxyl-N-desmethyl-tamoxifen (endoxifen) in the serum of these patients. 3. To correlate between the levels of tamoxifen/active metabolite enoxifen ratio and CYP2D6\*1,\*4 genotyping. 4. To investigate which is more valuable investigatory tool for prediction of the clinical outcome (response and/or toxicity) in these patients; either the measurements related to pharmacokinetics: tamoxifen/endoxifen levels or the pharmacogenetic analysis of CYP2D6 \*1,\*4.