Loss of Tumor Suppressor Genes Linked to DCIS Breast Cancer Progression in Study

Researchers from University of Texas Southwestern in Dallas and Thomas Jefferson University in Philadelphia have found that the combined loss of 2 tumor suppressor genes can help predict whether DCIS will progress into invasive breast cancer. This finding could help doctors make better informed decisions about how aggressively to treat DCIS.

Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. DCIS means cancer cells are inside the ducts but have not spread into the surrounding breast tissue. DCIS is often called a pre-cancer, because some cases may progress to invasive cancer. Because there isn’t a good way to tell which cases of DCIS will turn into invasive cancer, most women diagnosed with DCIS are treated. This involves surgery and sometimes radiation and/or hormone therapy. If doctors could tell which cases of DCIS would become invasive cancer, they could limit treatment to the DCIS patients who really need it. New ways of figuring out which DCIS patients are at risk of developing invasive breast cancer will help doctors avoid both over- and under-treatment.

The researchers studied 236 DCIS patients who had been treated with breast conserving surgery. They examined the breast tissue to look for the loss of 2 tumor suppressor genes, retinoblastoma (RB) and phosphatase and tensin homolog (PTEN). Tumor suppressor genes are normal genes that help slow down cell division, repair DNA mistakes, or tell cells when to die. When tumor suppressor genes don't work properly, cells can grow out of control, which can lead to cancer.

In the study, about one-third of the women had either a recurrence of DCIS (the cancer came back) or progression to invasive breast cancer. Women who lacked both RB and PTEN were more than 5 times as likely to develop invasive breast cancer. The study was published November 28, 2012 in the Journal of the National Cancer Institute.

An estimated 50,000 new cases of DCIS were diagnosed in women in 2012. The ability to determine which cases could be cured by surgery alone, and which needed additional therapy, would enable women to get the right treatment for their specific breast cancer type and risk factor. The researchers believe more studies on RB and PTEN will lead to a personalized approach to DCIS, replacing the current “one size fits all” treatment.

The American Cancer Society medical and editorial content team
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Retinoblastoma and Phosphate and Tensin Homolog Tumor Suppressors: Impact on Ductal Carcinoma In Situ Progression. Published November 28, 2012 in the Journal of the National Cancer Institute. First author: Erik S. Knudsen, University of Texas Southwestern, Dallas, Texas.

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