Dr. Linda Griffith was at a conference in Singapore in early January when she felt a lump in her breast…she had a mammogram, ultrasound and biopsy within hours of getting off the plane. The news was not good: she had cancer… had a test to see whether her tumor had extra copies of a protein, HER2. If it did, it would respond to a drug, Herceptin, which blocks the protein and stymies the tumor’s growth…

Estrogen receptor tests are a muddle, noted Dr. Edith Perez, a breast cancer specialist at the Mayo Clinic in Jacksonville, Fla. Quite a few tests are being used, but Dr. Perez could not ascertain exactly how many or how good they were in predicting whether a tumor would respond to estrogen-depleting drugs. And different labs may do tests in different ways; some even invent their own. “How do you know they are the same?” Dr. Perez asked. “If you do the test in two different labs, you can get two different answers.”

NY Times, by Gina Kolata, 4/19/2010

Tags: Cancer, Dr. Edith Perez, HER2