NanoString Technologies has reported positive results from a second validation study of its breast cancer assay based on the PAM50 gene expression signature.

The CE-marked breast cancer assay is designed to provide a subtype classification based on the fundamental biology of an individual’s breast tumor (intrinsic subtyping).

The assay also offers prognostic score (ROR score), which indicates the risk of distant recurrence in postmenopausal women with hormone receptor-positive (HR+) early-stage breast cancer treated with endocrine therapy alone.

The study, performed by British Columbia Cancer Agency (BCCA), evaluated 1,478 stored formalin-fixed paraffin-embedded (FFPE) patients samples using the nCounter Analysis system, installed at BCCA’s Center for Translational and Applied Genomics.

The patients who were evaluated are a part of the Austrian Breast & Colorectal Cancer Study Group 8 (ABCSG8) trial, reports US based life sciences company.

University of British Columbia pathology professor and study lead pathology investigator Torsten Nielson said the automated nCounter Analysis system is used in hospital pathology laboratory to accurately measure RNA extracted from standard FFPE tissue samples with minimal hands-on time.

"On these clinical specimens, 97% of the breast cancer samples that passed the pre-specified tissue and RNA metrics yielded intrinsic subtype and ROR results," Nielson added.

In addition to the primary and secondary endpoints, the study showed that Luminal A subtypes have better outcomes than Luminal B subtypes independent of nodal status in postmenopausal women with HR+ early-stage breast cancer treated with endocrine therapy alone.

The PAM50 gene signature is not cleared for sale in the US, while the nCounter Analysis system is labeled for research use only.