Many cancers cause malignant effusions, or the leakage/collection of fluid in the pleural lining surrounding the lungs. Malignant pleural mesothelioma is one of these cancers, yet even after draining fluid from the lungs and analyzing it, it is often difficult or impossible to make a definitive diagnosis. The presence of malignant cells in effusions has implications in diagnosis, tumour staging, and prognosis. If the fluid can be used to diagnose mesothelioma, time and expense can be saved for the patient, as well as suffering from invasive procedures currently used to diagnose meso.
The detection of malignant cells currently presents a challenge for cytopathologists. New methods are needed. The available molecular markers are extremely limited, which hinders definitive diagnosis for mesothelioma from the fluid alone. MN/CA9 has proved to be a valuable marker in many cancers such as lung, breast, colon, and kidney. This study evaluated MN/CA9 as a new molecular marker for the detection of cancer cells in pleural effusions with the hope that cancers such as mesothelioma can be more easily diagnosed.
Seventy-one pleural effusions including 59 malignant effusions from patients with cancer, and 12 patients with benign diseases as a control, were subjected to RT-PCR for detection of MN/CA9 gene expression. MN/CA9 gene expression was detected in 53/59 (89.8%) pleural effusions from cancer patients (15/16 for breast cancers, 10/11 for lung cancers, 4/4 for ovary cancers, 2/3 for colon-rectal cancers, 5/6 for cancers of unknown site, 7/8 for mesothelioma and 10/11 for other cancers). Furthermore, MN/CA9 was positive in 13/18 (72.2%) of cytologically negative effusions of cancer patients.
For mesothelioma patients, the detection of MN/CA9 gene expression in seven out of eight cases is promising because this gene marker may be a key to identifying the presence of mesothelioma in the pleural fluid.
MN/CA9 was detected in only 1/12 (8.3%) effusions from the control patients (p < 0.01). The sensitivity and specificity of MN/CA9 gene expression were, respectively, 89.8% and 91.7%. The preliminary results of this study suggest that MN/CA9 could be a potential marker for the detection of malignant cells in effusions. The authors of the study suggest a large-scale study in order to confirm these results.
From: Biomarkers. 2007 Mar-Apr;12(2):214-20., MN/CA9: a potential gene marker for detection of malignant cells in effusions. Li G, Passebosc-Faure K, Feng G, Lambert C, Cottier M, Gentil-Perret A, Fournel P, Pérol M, Genin C., Laboratory of Clinical Immunology, North Hospital, CHU of Saint-Etienne, France. firstname.lastname@example.org