In the late 1990's, a Research Scientist at Diagnostic Products Corporation (DPC), a biotechnology firm in Los Angeles, concentrated her efforts on experiments that were intended to speed development of a breast cancer test. She worked with the MCF-7 cells, cultured breast cancer cells, and she relied on technology developed by Cesar Milstein, George Kohler and Niels Jerne.

Those three European scientists had found a way to produce large batches of something called monoclonal antibodies. Monoclonal antibodies could recognize and bind to specific proteins. Mass-production of the right monoclonal antibody promised to give physicians a new test for breast cancer.

Monoclonal antibodies could be used in test kits. If scientists could identify a protein produced by breast cancer cells, and if they could then produce a monoclonal antibody that would bind to that protein, then those scientists would be well on their way to creation of a new breast cancer test.

Today, thanks to the efforts of devoted research scientists, there is a new breast cancer test. It was developed by DPC, and it is called the BR-MA assay. The BR-MA assay employs a tube coated with a monoclonal antibody, a tube that's examined by an Immulite machine.

The breast cancer test developed by DPC measures the level of CA15-3 in a patient's bloodstream. CA15-3 is a protein produced by all breast cells. Elevated levels of CA15-3 have been detected in 60% of preoperative breast cancer patients.

The protein CA15-3 exists on the membrane of the breast cells. Development of a test for breast cancer has required the growth in culture of large numbers of breast cancer cells. Those cells needed to be cultured under specific conditions. They had to be cultured in serum-free media, a type of media never-before used at DPC.

The serum-free media aided the performance of the next procedure, a procedure done in the Biochemistry lab.  Biochemists at DPC isolated the CA15-3 from the cultured cells. The isolated CA15-3 was then used to make monoclonal antibodies, chemicals needed for the creation of a breast cancer test.

The personnel in the Biochemistry lab worked closely with the personnel in the Molecular Biology lab. The researchers in the Molecular Biology lab used a Western Blot to confirm the claim that CA15-3 had indeed been obtained from the breast cancer cells.

The Western blot should not be seen as a technique that is used only for the making of a breast cancer test. The Western blot is a modification of the Southern blot, a blotting technique developed by an Oxford scientist. The Western blot has been used in the development of many different diagnostic tests.

Thanks to this new test for breast cancer, a patient does not always need to depend on the image provided by a mammogram. A patient can also be tested for the presence of CA15-3, a protein associated with the growth of breast cancer cells. A test for breast cancer can proceed in a doctor's office, and it does not require that the patient disrobe from the waist up.