Tumor Profiling

What is tumor profiling?

Tumor profiling tests give information about the genes in cancer cells. These genes are in the tumor cells, not in the normal (non-cancer) cells in a person’s body.

Tumor profiling tests look at patterns of expression for a set of genes in a sample of the tumor removed during a biopsy or surgery.

The gene profiles of some tumors may help predict whether or not the cancer is likely to metastasize (spread to other parts of the body) in the future [85]. Sometimes, this information can be used to guide breast cancer staging and treatment.

Tumor profiling may also be called genomic testing, molecular profiling or genetic signature testing.

Oncotype DX® is the most common tumor profiling test used in the U.S.

Tumor profiling and breast cancer staging

Oncotype DX is a tumor profiling test. Oncotype DX results can be included as part of breast cancer staging for some estrogen receptor-positive, HER2-negative, lymph node-negative tumors [167]. It’s the only tumor profiling test used in breast cancer staging today.

If Oncotype DX testing is done, the results are used in combination with other factors to determine breast cancer stage.

Learn about other factors that help determine breast cancer stage.

Tumor profiling and chemotherapy

Oncotype DX and MammaPrint® are tumor profiling tests recommended by the American Society of Clinical Oncology (ASCO) [85]. These tests may be used to help guide the use of chemotherapy for some people with estrogen receptor-positive, HER2-negative early breast cancer.

Oncotype DX testing

Oncotype DX tests a sample of the tumor for patterns of expression in a group of 21 genes. Oncotype DX looks at genes in the breast cancer cells, not in the normal (non-cancer) cells in a person’s body.

For some estrogen receptor-positive, HER2-negative early breast cancers, the results of the Oncotype DX test help predict the:

• Chance of metastasis (when cancer spreads to other organs) in the future
• Possible benefit of chemotherapy in addition to hormone therapy

If the Oncotype DX results show a low risk of metastasis, then chemotherapy may not be needed and the use of hormone therapy alone is standard of care [10].

In this way, Oncotype DX may help some people avoid chemotherapy and its side effects.

Learn more about Oncotype DX.

MammaPrint testing

MammaPrint tests a sample of the tumor for patterns of expression in a group of 70 genes. These genes are in the breast cancer cells, not in the normal (non-cancer) cells in a person’s body.

The results of the MammaPrint test help predict how likely some estrogen receptor-positive, HER2-negative early breast cancers are to metastasize (spread to other organs) in the future.

If the MammaPrint results show a low risk of metastasis, then chemotherapy may not be needed, and the use of hormone therapy alone is standard of care [10].

In this way, MammaPrint may help some people avoid chemotherapy and its side effects.

Learn more about MammaPrint.

Other tumor profiling tests

A few other tumor profiling tests may be used to guide chemotherapy use for some postmenopausal women who have estrogen receptor-positive, HER2-negative early breast cancers. These include:

• EndoPredict
• Prosigna (PAM50)

Tumor profiling and extended hormone therapy

Breast Cancer Index

Breast Cancer Index® is a tumor profiling test that looks at patterns of expression in a set of 11 genes to help predict how likely some breast cancers are to metastasize in the future.

Breast Cancer Index may be considered in making treatment decisions about the use of hormone therapy for more than 5 years for some estrogen receptor-positive, HER2-negative, lymph node-negative breast cancers [10,85].

Learn more about taking tamoxifen for more than 5 years.

Learn more about taking an aromatase inhibitor for more than 5 years.

Talk with your health care provider

If you have estrogen receptor-positive, HER2-negative early breast cancer, talk with your health care provider about whether tumor profiling would be helpful in guiding your breast cancer treatment.

Learn more about talking with your health care provider.

Treatment guidelines

Although the exact treatment for breast cancer varies from person to person, evidence-based guidelines help make sure high-quality care is given. These guidelines are based on the latest research and agreement among experts.

The National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) are respected organizations that regularly review and update their guidelines.

In addition, the National Cancer Institute (NCI) has treatment overviews.

Talk with your health care team about which treatment guidelines they follow.

After you get a recommended treatment plan from your health care team, study your treatment options. Together with your health care team, make thoughtful, informed decisions that are best for you. Each treatment has risks and benefits to consider along with your own values and lifestyle.

Updated 04/10/24