This article is more than 5 years old. Information may no longer be current.
Potential breath biomarkers of lung cancer identified
Compounds found as early as stage I disease.
Click Here to Manage Email Alerts
Researchers at Zhejiang University in Hangzhou, China, have identified potential biomarkers of lung cancer that are found in the breath of patients with the disease, even as early as stage I and stage II.
They identified 11 volatile organic compounds in the breath of patients with lung cancer. The compounds correlated with four volatile organic compounds found at the cellular level of four different lung cancer types.
According to their report, which was published in a recent issue of Cancer, the first correlation between breath compounds and lung cancer was in 1999, when 22 different volatile organic compounds were identified as lung cancer markers. However, prior to this study, there was no statistical correlation between the breath and cellular biomarkers.
“The specific compounds exhaled by lung cancer cells in the microenvironment are the source biomarkers of lung cancer and also serve as direct evidence that diagnosis of lung cancer by breath is possible,” the researchers wrote.
“However, there are few articles published regarding the correlation of biomarkers in the breath and biomarkers in the environment. Therefore, the noninvasive method of breath diagnosis for lung cancer cannot be supported by cellular evidence.”
Breath and cell correlation
Researchers obtained 49 breath samples and 16 lung tissues from 65 volunteers at a hospital in China. They acquired 13 breath samples from healthy individuals, 29 from patients with lung cancer and seven from patients with chronic bronchitis. All of the patients with lung cancer had been clinically diagnosed.
The researchers took the 16 lung tissues from patients undergoing thoracic surgery. All had lung cancer except for one, who had chronic bronchitis and emphysema. Breath samples were collected from 10 patients prior to surgery. The sample tissues included four types of lung cancer cells: squamous cell carcinoma, adenocarcinoma, bronchioloalveolar and non-small cell carcinoma.
Of the 11 volatile organic compounds the researchers identified, four were found in all cell types and viewed as general biomarkers. The researchers suspected that the remaining compounds were unique to each cancer type.
On the cellular examination, the researchers identified cancer cells on a lung tissue sample that was found normal on macroscopic examination. As a result, they found that patients with stage I and stage II disease had similar compounds in the tissue, in lesser concentrations, as those with stage III and IV disease.
Of the 49 breath samples, only three of those from patients with lung cancer had no detectable compounds. As a control, the researchers also examined the breath of healthy people. They found that the compounds in healthy people were less than those in patients with lung cancer.
Sensitivity and specificity
The breath test had a sensitivity of 86.2% for lung cancer, a specificity of 69.2% among healthy people and a specificity of 71.4% among patients with bronchitis.
“The differences between the volatile organic compounds present in the breath samples from lung cancer patients and the culture medium of lung cancer cells demonstrated the complexity of the transmission mechanism,” the researchers wrote. “Further study should be performed to determine the exact modular structure of the four components and the characteristic compounds.”
For more information:
- Chen X, Xu F, Wang Y, et al. A study of the volatile organic compounds exhaled by lung cancer cells in vitro for breath diagnosis. Cancer. 2007;110:835-844.