Recently approved breast cancer test based on Norwegian research

The newly approved Prosigna test for determining the need for adjuvant therapy for newly operated breast cancer patients is based on research performed at the Institute for Cancer Research. The Prosigna Breast Cancer Prognostic Gene Signature Assay (formerly called the PAM50 test), made by NanoString, is a genomic test that analyzes the activity of certain genes in early-stage, hormone-receptor-positive breast cancer. The Prosigna assay measures the expression of 50 genes (called the PAM50 gene signature) to estimate the risk of distant recurrence of hormone-receptor-positive breast cancer.

The molecular signature used in the PAM50 test is based on research performed by Professor Sørlie and colleagues as far back as 2000. In several articles they demonstrated for the first time the clinical impact of the five “intrinsic” molecular subtypes of breast carcinomas. They investigated the prognostic value of the gene expression profiles by analyzing breast tumor biopsies from patients enrolled in a prospective neoadjuvant study. The results showed that diversity in gene expression across breast tumors reflected biological diversity, which influenced their clinical behavior.

The fundamental biological nature of the intrinsic molecular subtypes of breast cancer has since been repeatedly validated and supported by integrated molecular analysis across several molecular layers. In retrospect, the intrinsic subtypes have become an established terminology, and they have provided an increased understanding of the biology of breast cancers and the signaling pathways involved in their progression.

Implementation of Prosigna is expected to result in reduced overtreatment of breast cancer patients with low-risk of recurrence, an important step in further personalization of cancer medicine. 


Articles in Norwegian:

Details about the Prosigna test (from

Endelig ja til lovende brystkrefttest! (from

Sykehusene får ta i bruk ny brystkreft-test (from

Researchers involved in the EMIT study - Establishment of Molecular profiling for Individual clinical routine Treatment decisions in Early Breast Cancer, receiving Klinbeforsk support amounting to 20 mill NOK in 2017.
From left.: Bjørn Naume, Therese Sørlie, Hege Russnes, Hege Oma Ohnstad, Elin Borgen, Gry Geitvik.
Photo: Per Marius Didriksen


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