PAM50 (Prosigna®) is a tumor profiling test that helps determine the benefit of using chemotherapy in addition to hormone therapy for some estrogen receptor-positive (ER-positive), HER2-negative breast cancers.
Tumor profiling
Every cell in your body has genes that contain the blueprints (genetic code) for your body. Similarly, every cell in a breast tumor has genes. These genes contain the blueprints for the tumor.
Tumor profiling (using gene expression profiling tools) gives information about the genes in cancer cells. Prosigna is a tumor profiling test.
PAM50 (Prosigna) testing
PAM50 stands for Prediction Analysis of Microarray 50. It tests a sample of the tumor (removed during a biopsy or surgery) for a group of 50 genes.
Along with other factors, the results of the PAM50 (Prosigna) test help predict the chance of metastasis (when cancer spreads to other organs).
Progisna also helps to determine the molecular subtype of breast cancer.
PAM50 (Prosigna) scores
If the Prosigna test shows the breast cancer has a fairly high risk of metastasis (the PAM50 score is high), a more aggressive treatment plan that includes both hormone therapy and chemotherapy may be advised [38-41].
If the test shows a low risk of metastasis (the PAM50 score is low), the use of hormone therapy alone may be considered.
In this way, Prosigna may help some people avoid chemotherapy and its side effects.
When can PAM50 (Prosigna) be used?
PAM50 (Prosigna) helps predict the chance of metastasis for postmenopausal women with breast cancers that are all of the following [38-41]:
- Stage I or II
- ER-positive (and will be treated with hormone therapy)
- HER2-negative
- Lymph node-negative
Under study
Some findings show PAM50 (Prosigna) may help identify which ER-positive breast cancers may benefit from hormone therapy beyond 5 years [41].
However, Prosigna is not recommended for use in guiding extended hormone therapy use at this time [38].