The ISET (Isolation by Size of Epithelial Tumor Cells) and the CellSearch Methods in Malignant Pleural Mesothelioma

Detection and Characterization of Circulating Tumor Cells in Patients With Malignant Pleural Mesothelioma: Towards a New Phase in the Understanding of the Natural History of This Cancer?

Malignant pleural mesothelioma (MPM) has a growing incidence and in spite of early diagnostic, their outcome remains dismal. The evolution of MPM is often local with rare distant metastases. There is now a sizable body of evidence that metastases could develop from circulating tumor cells (CTC) spread in blood before or during surgery. Thus, sensitive and specific detection of CTC in blood is considered as a potentially relevant predictive biomarker for patients with carcinomas. In exchange, the prognostic value of CTC in MPM has not yet been evaluated.

Indeed, the main goal for preoperative detection of CTC is to identify patients with high risk of recurrence after surgery, in order to perform more adapted therapeutic strategy. Despite several studies reported about CTC detection, methodological aspects concerning sensitivity, specificity and reproducibility have prevented a clear appraisal of their clinical impact. Thus, the aim of our study is to evaluate the presence and the prognostic value of CTC in MPM by a double approach. In our setting, cytopathological analysis of circulating non hematological cells (CNHC), of epithelial origin, isolated according to their size (ISET, Isolation by Size of Epithelial Tumor cells) along with immunomagnetic selection, identification and enumeration of circulating epithelial cells in peripheral blood (CellSearch method) is considered a promising approach.

Inclusion Criteria

For the patients:

• Age > 18 years
• Patient having been operated for a strong suspicion of a pleural malignant tumoral lesion corresponding to a primitive pleural mesothelioma
• Signed patient consent

For the control subjects:

• Age > 18 years
• unhurt of any malignant or mild tumoral pathology or patients that must benefit from a surgical procedure for a benign lesion in other organ than the pleura or a pulmonary non tumoral lesion
• Signed patient consent

Exclusion Criteria :

• Patient with histories of cancer or the other synchronous cancer
• Patient with additives treatments
• Patient according to treatments additives others than protocols codified (in particular, platinum navelbine or gemcitabine platinum) for stages II
• HIV, hepatitis B or C infections
• Pregnant women