Proteins in Blood May Help Test for Lung Cancer

Proteins in Blood May Help Test for Lung Cancer

According to an article recently published in the Journal of Clinical Oncology, four proteins that can be measured in circulating blood may be strongly associated with the presence of lung cancer.

Lung cancer is responsible for more deaths every year in the United States than breast cancer, colon cancer, and prostate cancer combined. One of the main reasons that lung cancer remains so deadly is that it is often diagnosed once it has spread from its site of origin. In an effort to diagnose the disease in its earliest and most treatable stages, research is focused on identifying effective screening measures for lung cancer.

In order for new screening methods to be adopted into routine clinical care, the measures must identify cancer early enough to improve outcomes, must be economically feasible, and must detect cancer to an acceptable degree of accuracy. As well, in order to encourage patient compliance, screening measures must not be too invasive, painful, or have the potential for extreme side effects. To date no screening measures for lung cancer have been identified that provide a confirmed benefit.

Researchers from Duke University recently conducted a clinical trial to evaluate the potential association between specific proteins in the blood and the presence of lung cancer. This trial included 50 patients who were healthy when the trial started, 82 patients who had been diagnosed with non–small cell lung cancer, and 22 patients who had been diagnosed with small cell lung cancer. Patients had their blood drawn and tested for four specific proteins: carcinoembryonic antigen (CEA), retinol binding protein (RBP), alpha-1-antitrypsin (AAT), and squamous cell carcinoma antigen (SCCA).

  • The researchers established three separate groups based on levels of three proteins. 90% of patients whose protein levels fell within any one of these three groups had lung cancer.
  • However, although 90% of patients who fell into these groups had lung cancer, only 57% of all lung cancer patients had protein levels that fell into any of these groups. Therefore, this test really could not be used on its own as a screening tool for lung cancer. It could, however, indicate with approximately 90% accuracy that a patient whose protein levels fall into one of these groups should receive further testing with a biopsy.

The researchers concluded that this test may help determine which patients may need a biopsy following an irregular chest X-ray or scan including the lung. In addition, once these results are validated and this approach can be combined with other screening measures to improve identification of early lung cancer, these groupings may be useful in lung cancer screening.

Patients who are at a high risk of developing lung cancer may wish to speak with their physician regarding their individual risks and benefits of participating in a clinical trial further evaluating screening measures. Two sources of information regarding ongoing clinical trials include the National Cancer Institute ( and

Reference: Patz E, Campa M, Gottlin E, et al. Panel of serum biomarkers for the diagnosis of lung cancer. Journal of Clinical Oncology. 2007;25:5578-5583.

Related News:Blood Test May Help Detect Early Lung Cancer (10/11/2007)

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