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New Molecular Test For Postmenopausal Breast Cancer | Mammostrat September 6, 2007

Posted by ramunas in breast cancer, mammostrat, sporadic cancer, technology.

The Molecular Profiling Institute, Inc. has just announced that they are now providing Mammostrat, a new molecular-targeted breast prognostic test, to breast cancer patients, nationwide in the USA. The Mammostrat prognostic test utilizes five immunohistochemical (IHC) biomarkers a diagnostic algorithm.to classify patients into high, moderate, or low-risk categories for disease recurrence.

Acctually, it is not a true genetic test. Mammostrat is a five-antibody immunohistochemistry (IHC) prognostic test for postmenopausal, estrogen receptor-expressing, hormone receptor-treated (tamoxifen) breast cancer patients with node-negative disease who will receive hormonal therapy and are considering adjuvant chemotherapy. It utilizes standard paraffin-embedded tissue (via and via) .

The five markers are as follows:

  • p 53 , which is known to play a central role in cell cycle regulation and mutations in p53 contribute to tumor formation (aka “the Guardian of Genome”)
  • HTF9C , which is co-expressed with proteins that are involved in DNA replication, implicating HTF9C in DNA replication and cell cycle control.
  • CEACAM5 , which is normally expressed in embryonic tissue and is aberrantly expressed in some cancers.
  • NDRG1, which is expressed under conditions of hypoxia and other stresses. It may have a role in helping tumors survive under the hypoxic, stressful environment confronting aggressive tumors.
  • SLC7A5, which is involved in nutrient transport. Over-expression of SLC7A5 could help sustain the high growth rate of cancer cells by increasing a cell’s ability to consume nutrients.

Mammostrat testing is performed by staining the supplied sections and appropriate control tissue with the five Mammostrat antibodies. A trained pathologist will then score the stained slides according to established criteria. A “0” for negative staining or a “1” for positive staining for each antibody will be entered into the AGI algorithm to calculate a “Risk Index.” The Risk Index value will be used to classify the patient as low, moderate, or high likelihood of breast cancer recurrence. The ordering pathologist will receive a report similar to the sample report shown here. The Mammostrat report will list the staining result for each antibody, the Risk Index category (i.e. low, medium, or high) and an interpretation of what the score means for the patient.

Pathologists, oncologists and patients should use the Mammostrat test results in conjunction with other clinical information to help select amongst treatment options (via).

Because Mammostrat uses traditional immunohistochemistry technology, the test is expected to be significantly less expensive than existing molecular-based, prognostic tests for breast cancer and is typically covered by insurance.

“Mammostrat’s cost-effective, molecular-targeted analysis enables MPI to provide the test at a significant discount compared to our competitors. Moreover, test results will be available quickly — an average of seven business days — versus two weeks for alternative, comparable tests.” , says Todd Maney, Ph.D., Vice President of New Product Development.

The test was developed by Applied Genomics, Inc (AGI). who rigorously translated recent genomic insights in cancer into a novel immunohistochemistry test. Mammostrat test results have been validated using over a thousand patient samples in North America.

AGI also has developed PulmoType and PulmoStrat IHC based antibody tests for lung cancer.

The standard of care for most of postmenopausal women with estrogen receptor expressing, node negative breast cancer is surgery to remove tumor followed by hormone signaling targeted therapy (e.g. tamoxifen or aromatase inhibitors) (ref.).

The prognosis for this group of early stage, estrogen receptor positive breast cancer patients is considered favorable with approximately 90% or more of these patients surviving five years and longer. However, several studies have demonstrated that outcomes can be further improved by treatment with cytotoxic chemotherapy. Since it is clear that most patients will remain disease free in the absence of additional therapy it is likely that cytotoxic therapy is only important for a small subset of these early-stage cancers. Since chemotherapy comes with difficult side effects (e.g. nausea, hair loss, severe fatigue) and long term risk of cardiovascular complications and secondary tumors, the decision whether to use adjuvant chemotherapy is difficult and controversial. The potential benefit of using Mammostrat testing is to identify those patients at high risk of cancer recurrence and therefore more likely to benefit from additional chemotherapy as opposed to those patients at low risk of recurrence who may choose to forgot chemotherapy.

I think it would be of interest to include these protein encoding genes into some gene expression profiling test as well.