NEW ORLEANS (Reuters Health) - In hormone receptor-positive metastatic breast cancer, a single nucleotide polymorphism (SNP) is associated with improved treatment efficacy of the aromatase inhibitor letrozole (Femara), a study has shown.
The presence of this mutation, in the 3' untranslated region (UTR) of the human aromatase gene CYP19, was associated with a more than doubling in time to progression in letrozole-treated women in the study.
“If confirmed in larger studies, this small genetic alteration may help in selecting patients for letrozole therapy,” Dr. Ramon Colomer from Institut Catala d-Oncologia in Girona, Spain told the 40th Annual Meeting of the American Society of Clinical Oncology Saturday.
He and colleagues evaluated the predictive value of 2 different SNPs of the CYP19 aromatase gene in tumor tissue samples from 65 women treated with letrozole for metastatic breast cancer. Forty six percent of the women had a SNP of CYP19 UTR and 63% had a SNP in the intronic region of CYP19.
According to Dr. Colomer, time to treatment progression after letrozole therapy
was significantly longer in women with SNPs of CYP19 UTR compared with women with wild-type CYP19 UTR (525 days vs 196 days, p = 0.02). SNPs in the intronic region of CYP19 did not increase time to treatment progression after letrozole (459 days vs 510 days, p=0.9).
“In the last six months, we have found a way of looking at this alteration not in tumors but in blood,” Dr. Colomer reported, which would aid in the development a commercial test.
MeSH Headings:Breast Neoplasms: Congresses: Health Care Economics and Organizations: Neoplasms: Neoplasms by Site: Organizations: Polymorphism, Single Nucleotide: Diseases: Health CareCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.