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CYP2D6 genotyping

Indications: - assessment of tamoxifen metabolism [3] Clinical significance: - cytochrome P450 2D6 activates tamoxifen to 4-hydroxy-N-desmethyl-tamoxifen (endoxifen) the most active metabolite of tamoxifen (in terms of estrogen binding - individuals with homozygous mutations may be poor metabolizers of tamoxifen; thus poor activators of tamoxifen & poor responders to therapy - apparently the may be ultra-rapid metabolizer forms as well [2] Laboratory: - see ARUP consult [2]

Related

cytochrome P450 2D6 (cytochrome P450 2D, cytochrome P450 DB1, debrisoquine-4-hydroxylase, CYP2D6) tamoxifen (Novaldex, Soltamox)

General

genotyping (allele testing)

References

  1. Cytochrome P450 2D6 Genotype for Tamoxifen Hormonal Therapy Mayo Clinic http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/87966
  2. ARUP Consult: CYP2D6 Genotyping - Tamoxifen deorecated reference
  3. Kuznar W Guidance Issued for Tamoxifen Based on CYP2D6 Genotyping. Poor metabolizers may require increase in dose or a switch to an aromatase inhibitor. MedPage Today. ASCO Reading Room 03.20.2018 https://www.medpagetoday.com/reading-room/asco/breast-cancer/71868 - Goetz MP, Sangkuhl K, Guchelaar HJ, et al Clinical pharmacogenetics implementation consortium (CPIC) guideline for CYP2D6 and tamoxifen therapy Clin Pharmacol Ther. 2018 Jan 31 PMID: 29385237

Component-of

CYP2D6 & CYP2C19 genotyping panel