Understanding MammaPrint Results

Risk categories, the MammaPrint Index and what to discuss when the report arrives

Key takeaways

• MammaPrint assesses a 70-gene expression signature in breast-tumor tissue.^[2]
• The index is not a percentage, cancer stage or measure of how much tumor remains.
• High risk does not mean recurrence is certain; low risk does not mean recurrence is impossible.
• Use the categories and explanatory notes on your own report version.
• Any treatment decision needs the full clinical picture and a discussion with the treating oncologist.

What the result is describing

A MammaPrint result describes a tumor gene-expression pattern associated with recurrence risk. Its category and index need to be read with the report legend, pathology and clinical history—not as a standalone instruction about chemotherapy.

MammaPrint is intended to add information about recurrence risk in an appropriate early-stage breast-cancer setting. It examines gene activity in the tumor rather than searching for a single inherited mutation. Agendia describes the output as a MammaPrint Index with an associated risk classification.^[2]

The result belongs to the tested tumor specimen. It does not establish whether a relative has increased inherited risk, confirm whether cancer has spread elsewhere or replace imaging and pathology. If your main concern is family risk, that is a separate question to raise with the clinician or genetic counsellor. Oncquest lists MammaPrint plus BluePrint as a combined gene-expression offering.^[1][7]

Report element	How to read it
Risk category	Use the label and explanatory notes supplied with the actual report.
MammaPrint Index	A gene-expression score; not a percentage chance of recurrence.
Further risk grouping	UltraLow, Low, High 1 or High 2 may appear in relevant materials or report versions.
Study outcome figures	Population estimates with particular follow-up and treatment assumptions.
BluePrint result	A separate molecular-subtype output, not a second MammaPrint risk score.

Start with the report, not an online score example

Check identity, specimen source, collection date, issue date and the exact assay name. For the Oncquest MammaPrint plus BluePrint combination, keep both outputs together, including comments and the BluePrint page. If more than one report was issued, ask which version is current. The combination uses tumor gene expression; it is not an inherited-risk or broad mutation panel.^[1]

Agendia's published example reports show an index on a scale from -1 to +1, with negative values on the high-risk side and positive values on the low-risk side. This orientation is easy to misunderstand: a larger positive number is not automatically more dangerous. An example on a website illustrates the format, not your personal prognosis.^[3][4]

What the index can and cannot tell you

The index summarises a gene-expression pattern. It is not a probability: an index of +0.30 does not mean a 30% recurrence risk. Nor is it a count of mutations, a percentage of cancer cells or a measure of tumor size. Use the assay-specific interpretation rather than translating the decimal yourself.

The manufacturer sample reports also include a caution about classification near the risk boundary. If the value is close to that boundary, ask the oncologist to review the laboratory's explanatory text and whether clarification is needed. Do not round a value, discard its sign or apply a cutoff remembered from a different test.^[3]

Low risk, UltraLow, High 1 and High 2

You may encounter a broad High Risk or Low Risk classification, and also the terms UltraLow, Low, High 1 and High 2 in more detailed MammaPrint materials. Agendia's published research materials describe these as further groupings along the index. The naming is not identical across every historical example and current report format.^[5]

Do not retrospectively relabel an older report from an online chart. Ask whether the additional grouping has been formally reported for your assay version and what evidence is relevant to your clinical situation. UltraLow does not mean zero risk, and High 2 is not a cancer stage. These labels describe the genomic result, not a complete treatment plan.

Why a risk category is not a personal certainty

Risk statements are based on groups studied under defined conditions. Their meaning depends on the outcome measured, the follow-up period, the patients included and the treatment they received. A distant-recurrence endpoint is not automatically the same as any recurrence, overall survival or lifetime risk.

The manufacturer example reports include group outcome figures and explain their study context. Those percentages should not be copied into a personalised prediction without clinical interpretation. Ask which estimate, if any, is appropriate for you and whether it describes outcomes with a particular treatment. A category can inform a discussion without predicting exactly what will happen to one person.^[4]

Put genomic risk beside clinical risk

Tumor size, nodal involvement, grade, hormone-receptor status and HER2 findings remain important parts of breast-cancer assessment. Age, menopausal status, general health and the treatment setting can also affect the discussion. A genomic result adds a different type of information rather than erasing these existing findings.^[8]

If the clinical picture and genomic category seem different, ask the team to explain the distinction. Different does not automatically mean that one test is wrong. A useful consultation identifies what is known from each source, where uncertainty remains and how the combination changes—or does not change—the options under consideration.

What the result means for a chemotherapy discussion

The report can contribute to a discussion about the expected benefit and burdens of systemic treatment in the appropriate setting. It should not be converted into a universal rule that everyone with low genomic risk can omit chemotherapy or everyone with high genomic risk needs the same regimen.

Ask the oncologist to explain the evidence that applies to your age, menopausal status, nodal findings and receptor status. It is helpful to discuss absolute benefit, relevant uncertainties and side effects in plain language. A report alone is not a reason to stop prescribed endocrine therapy, cancel surgery or alter a treatment plan. Those decisions require review of the complete clinical circumstances.^[2]

Read BluePrint as a separate output

When both tests are ordered, BluePrint adds a functional molecular-subtype result. It uses an 80-gene signature to classify a tumor as Luminal-type, HER2-type or Basal-type. In this combined framework, MammaPrint risk can further distinguish Luminal A-type from Luminal B-type among Luminal tumors.^[6]

The two results answer related but different questions. A molecular HER2-type label should not be silently substituted for the routine pathology HER2 result. Bring ER, PR, HER2 and the full genomic report to the consultation. If the results appear discordant, ask how the team interprets them together rather than assuming that one cancels the other.

A checklist for the results appointment

• What is the formal category on this report, and what does the index mean in this version?
• Does the report contain a boundary caution or any quality limitation?
• How does genomic risk compare with the clinical and pathology assessment?
• Which outcome and time period are being discussed when a risk percentage is quoted?
• What evidence applies to my treatment setting and menopausal status?
• Would this result change the plan, and what are the benefits and disadvantages of each option?

Verified Oncquest offering facts

1

Combined offering

Oncquest's oncology diagnostics portfolio includes MammaPrint plus BluePrint under test code SMO10242.

2

Diagnostic context

The offering brings Agendia's recurrence-risk and functional-subtype tests into the same order, while Oncquest's wider services include surgical pathology and IHC.

Why it matters for you

Keep the genomic findings alongside the original breast-pathology results when discussing what they add to your care.

If your Oncquest combination report is incomplete or its index and category appear inconsistent, contact Oncquest at 0124 6650000 or life@oncquestlabs.com to ask for report clarification. Quote the report reference and test code SMO10242. Bring the complete authorised report to your oncologist and record the agreed interpretation and next step; a score alone should not determine treatment.^[1][10]

Frequently asked questions

FAQs

Is a positive MammaPrint Index a positive cancer test?

No. Here positive describes the sign of an index on the assay’s scale. The test is performed on an already identified tumor and is not a yes-or-no test for the presence of breast cancer.

Does a negative index mean a good result?

Not in the usual sense of a negative screening test. Manufacturer examples place negative index values on the high-risk side. Always read the formal category and report legend.

Does Low Risk mean no chemotherapy?

Not automatically. The oncologist interprets genomic and clinical risk together and discusses the evidence applicable to the individual treatment setting.

Does UltraLow mean I can stop endocrine therapy?

No. Do not stop or shorten prescribed treatment from a category alone. Ask the treating team what evidence applies and whether any change is appropriate.

Why does an older report only say High or Low?

Report formats and the detail presented can differ. Ask the issuing laboratory or clinician to interpret the actual report rather than assigning new categories yourself.

Does MammaPrint show whether my children have inherited risk?

No. Tumor gene-expression profiling is different from germline testing. Family-risk concerns may warrant a separate assessment and genetic counselling.

Sources

1. Oncquest — MammaPrint + BluePrint Combination Official combination offering, method and sample requirements.
2. Agendia — MammaPrint Manufacturer context on the 70-gene signature and clinical interpretation.
3. Agendia — MammaPrint High Risk Example Report Published example, version 2020MAR; report layout, index and boundary caution.
4. Agendia — MammaPrint Low Risk Example Report Published example, version 2020MAR; category and study-context notes.
5. Agendia — MammaPrint Index Research Poster, SABCS 2024 Research example of further index groupings; not a personalised treatment calculator.
6. Agendia — BluePrint Manufacturer context on the 80-gene functional subtypes.
7. National Cancer Institute — Genetic Testing Fact Sheet Inherited-risk testing, consent and genetic counselling.
8. National Cancer Institute — Breast Cancer Types Context on breast-cancer classifications and biomarkers.
9. Oncquest — Company Overview Oncology focus, specialised diagnostic disciplines and laboratory network.
10. Oncquest — Patient Services and Enquiries Test search, centre search, online report access and published enquiry contacts.