SAN ANTONIO (EGMN) - Universal testing with the 21-gene Oncotype DX assay at diagnosis of estrogen receptor-positive breast cancer could save $330.8 million annually in the United States through avoidance of ineffective chemotherapy, according to a retrospective study involving analysis of nearly 200,000 estrogen receptor-positive tumor samples."We believe a low risk score on the assay is presently the most reliable biomarker for a chemotherapy-resistant phenotype. And we believe that the excess...