The Who, What, Where, When and Sometimes, Why.

PAM50 (Prosigna)

PAM50 (Prosigna®) is a test that helps show whether some estrogen receptor-positive (ER-positive), HER2-negative breast cancers are likely to metastasize (spread to other organs).

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 cancer.

Tumor profiling (using gene expression profiling tools) gives information about the genes in cancer cells. You may also hear the terms genomic testing and molecular profiling.

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.

The results of the PAM50 (Prosigna) test help predict the chance of metastasis for some ER-positive, HER2-negative breast cancers.

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 [42-43].

If the test shows a low risk of metastasis (the PAM50 score is low), the use of hormone therapy alone may be considered [14,42-43].

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 [14,42-43]:

  • Tumor size no larger than 5 cm
  • ER-positive (and will be treated with hormone therapy)
  • HER2-negative
  • Lymph node-negative or lymph node-positive with 1-3 positive nodes

Under study

PAM50 (Prosigna) is under study to see whether or not it may help identify ER-positive breast cancers that may benefit from hormone therapy beyond 5 years [44].

Updated 11/16/21