Breast Cancer Risk and Scientific Developments

Kevin Knopf, MD Health Guide
  • Greetings! I start my new position in San Francisco on October 3 so I am very excited by many things.

    There are two breast cancer items this month of note – the first a molecular step forward, the second a clinical step forward.

    A press release came to me about a publication that appeared in Science Express. Dr Velculescu at Johns Hopkins and others have identified 200 mutated genes associated with breast (and colon) cancer. Genes are made up of segments of DNA which is a long chain made up of smaller segments called nucleotides – these researchers found 1,500 nucleotides out of 465 million examined whose mutations are key to breast and colon cancer – quite an amazing feat. This corresponds to 200 genes.
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    Why is this important? This basic science work, or molecular biology, is key to understanding the causes of breast cancer which has profound implications for prevention. An understanding of these mutated genes will ultimately lead to a better understanding of what it is that makes a breast cancer cell different from a regular cell. This difference can then be exploited with “rational” therapies – so we hope this work will lead to large advances in treatment of breast cancer. A step towards a cure, if you will, and a large one that is quite an accomplishment.

    I’m saying goodbye to one of my dearest patients, “Gina,” who has had metastatic breast cancer for 8 years. She was excited to turn 40 this past year, and I was thrilled too. She comes in weekly for Herceptin (I’ve offered to change to every 3 weeks but she has been a little superstitious) – I think 2 years ago she had growth of a metastasis that went away nicely when we added Xeloda (Capecitabine) to Herceptin – now she is on herceptin alone and doing fine.

    We often discuss what looks promising in cancer research and I mentioned there is a new drug called Lapatanib that will go before the FDA soon for approval. It is a pill that blocks two receptors found on the breast cancer cell – EGFR1 and EGFR2 (for epidermal growth factor receptor). EGFR2 is a synonym for HER2, which is the target of Herceptin. What’s interesting about lapatanib is that it can still work in patients whose cancer has become resistant to Herceptin. We participated in the clinical trial of Lapatanib/Capecitabine vs. Capecitabine that showed a survival advantage to both agents. Where Lapatinib belongs in the treatment regimen is not yet entirely clear but there is enthusiasm about this new drug.

Published On: September 27, 2006