ASCO Meeting Features First Independent Comparison of Breast Cancer Genomic Tests

The combined MammaPrint and BluePrint genomic tests provide more information about the specifics of breast cancer than does the older, 21-gene test, according to the first independent assessment comparing the assays. That study was among the major new findings about breast cancer molecular diagnostics – also called genomic tests – emerging from this year’s recent annual meeting of the American Society of Clinical Oncology (ASCO).

Brufsky for DD blogAlso featured at ASCO were new insights about breast cancer in African-American women, drawn from research with MammaPrint and BluePrint conducted in the nation’s capital.

Together, the 70-gene MammaPrint and 80-gene BluePrint tests definitively categorize patients as Low Risk or High Risk for breast cancer recurrence and provide additional information about the specific biology of the cancer. The older and less sophisticated 21-gene test, on the other hand, stratifies patients into three risk-recurrence categories: Low Risk, High Risk, and Intermediate.

Low Risk means that patients can safely avoid chemotherapy and the often debilitating and damaging side-effects that can accompany it. High Risk results mean that patients should consider chemotherapy because of the substantial chance their cancer may recur without it.

But the 21-gene test also has an often confusing “intermediate risk” result, which was the case in nearly 37% of the samples examined by researchers at the University of Pittsburgh Medical Center (UPMC). An intermediate score gives no clear indication about whether a patient can safely avoid chemotherapy or not. This is not an issue with MammaPrint, which provides definitive results about the risk the breast cancer will recur.

The unambiguous nature of MammaPrint results is “valuable information because it can help us better determine how best to treat each patient,” said study co-author Adam Brufsky, M.D., Professor of Medicine at UPMC. “With a high-risk, low-risk finding, you don’t have the uncertainty that occurs in the intermediate range.”

Lead study author David J. Dabbs, M.D. noted that “together, MammaPrint and BluePrint reassign a substantial number of intermediate recurrence scores into ‘Low’ or ‘High’ risk, based on tumor intrinsic phenotype and gene expression analysis.” Dr. Dabbs is Chief of Pathology at Magee-Womens Hospital of UPMC.

Dr. Brufsky also spoke about the importance of the molecular subtyping of breast cancer provided by the Blueprint test: “By looking at the activity of the genes through molecular subtyping, the 80-gene test tells us more about what’s happening in the cancer cells,” he said. You can see a video of Dr. Brufsky discussing the study here.

Subtyping helps physicians make treatment choices that are more personalized to each patient’s tumor, because it helps predict how that tumor subtype will respond to targeted therapies both before and after lumpectomy surgery. The 21-gene test does not provide subtyping. Indeed, BluePrint is the only widely available test that classifies tumors by molecular subtype.

Molecular subtyping also played a role in another study presented at ASCO. The African-American women in this study – a group of 100 — were more likely to be diagnosed with higher-risk breast cancer. This was true no matter what the stage of their disease.

The researchers, from MedStar Washington Hospital Center, in Washington, D.C., used MammaPrint to show whether patients were at low risk or high risk of cancer recurrence. BluePrint was then used to determine if a tumor’s molecular subtype predicted a favorable outcome or not.

Raquel Nunes, M.D., a medical oncologist at the Washington CanNunes photocer Institute and a co-author of the study, said that “this work is particularly meaningful for us because it complements our interest in health disparities.” Click here to see a video of Dr. Nunes summarizing the study.

MammaPrint and BluePrint are offered exclusively through Agendia, a Dowling & Dennis client. The ASCO meeting took place May 30 – June 3 in Chicago.

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