NanoString Technologies, a US-based molecular diagnostic products provider, has announced that its PAM50 gene signature-based breast cancer assay offers prognostic information in endocrine-treated patients with HR+ node negative disease and allows improved differentiation of intermediate and high-risk groups.

"The aims of this study were to find out if the PAM50 gene signature offered prognostic information to clinical-pathological variables."

The firm announced that its TransATAC clinical validation study for its Prosigna Breast Cancer Prognostic Gene Signature Assay evaluated three kinds of cancer test, in order to predict the risk of a recurrence in the distant future in postmenopausal women, who have undergone endocrine therapy for hormone receptor-positive (HR+) early-stage breast cancer.

For the study, 1,017 samples were considered from the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial of postmenopausal women with HR+ early-stage breast cancer, who have been treated with endocrine therapy for five years.

The aims of this study were to find out if the PAM50 gene signature offered prognostic information to clinical-pathological variables and compare the performance of the PAM50 risk of recurrence (ROR) score, the Oncotype DX recurrence score (RS) and the IHC4 score, basically derived from immunohistochemical assessment of genes such as ER, PR, HER2 and Ki67.

The study authors concluded that the PAM50 ROR score offered more prognostic information than Oncotype DX RS, which is widely used.

Furthermore, unlike Oncotype DX RS, the PAM50 ROR score classified fewer patients under the intermediate-risk group and more under the high-risk set, after using prospectively defined risk cutoffs for low, intermediate and high risk of less than ten percent, between ten and 20% and greater than 20% estimated risk of recurrence, respectively.

It was found that the PAM50 ROR score also offered as much information as the IHC4 and could probably provide more information in the node negative / HER2 negative patient group.

This study, titled ‘Comparison of PAM50 risks of recurrence (ROR) score with Oncotype DX and IHC4 for predicting risk of distant recurrence after endocrine therapy’, was published in the Journal of Clinical Oncology (JCO).

NanoString Technologies president and CEO Brad Gray noted that the publication of the TransATAC study is an important milestone in its ongoing effort to enable genomic testing for breast cancer in local laboratories worldwide.

"We look forward to discussing the results and conclusions of this study with oncologists, pathologists and payers in the European Union and other countries that recognise the CE Mark, as we continue with our commercial launch in those regions," Gray added.