SULT1A1 concordance between whole blood and breast cancer tissue

Abstract

14090 Background: The human sulfotransferase (SULT1A1) enzyme is involved in the conjugation of tamoxifen. Studies have demonstrated the significance of polymorphisms within the SULT1A1 gene in relation to breast cancer survival and tamoxifen metabolism (Nowell et al, J Natl Cancer Inst 2002). DNA for genotyping in previous studies was obtained from a number of different biological specimens including whole blood or paraffin-embedded formalin-fixed tissue. The purpose of this study was to evaluate the genotypic concordance of SULT1A1 polymorphisms in whole blood and breast cancer tissue. Methods: Breast cancer patients receiving tamoxifen and previously genotyped for the SULT1A1 gene were consented for enrollment. Samples representing each of the three possible genotypes (*1/*1, *1/*2,*2/*2) were selected for the collection of archived tissue. DNA was extracted from whole blood using the QIAamp Blood Midi Kit (Qiagen Inc., Valencia, CA, USA) and from formalin-fixed paraffin-embedded breast cancer tissue using the QIAamp DNA Mini Kit (Qiagen Inc., Valencia, CA, USA) as per protocol. Genotyping of the SULT1A1 gene was conducted using a validated Pyrosequencing assay. Results: Tissue samples representing each of the three different SULT1A1 genotypes were compared to the whole blood genotypes. Each of the clinical samples demonstrated 100% concordance between the two different specimens. Conclusion: Our data provides evidence to support the genotyping of clinical samples for the SULT1A1 gene utilizing either whole blood or tumor tissue from breast cancer patients. No significant financial relationships to disclose.