Identification of neoplastic cells in peripheral blood by flow cytometry in patients with B-cell non-Hodgkin's lymphoma

Introduction: Non-Hodgkin lymphoma (NHL) is the most common hematological neoplasm in the world (1). New techniques have been studied to allow for faster diagnosis of the disease, such as flow cytometry immunophenotyping (FCI). Methods: The possibility to identify the presence of circulating tumor cells (CTCs) in the peripheral blood of patients with NHL was attempted through FCI, and the findings were compared with the initial staging by bone marrow biopsy. Peripheral blood samples from nine patients with NHL were evaluated using a panel of monoclonal antibodies in order to detect B-cell chronic lymphoproliferative disorders. Results: Bone marrow biopsies and peripheral blood FCI were found to be discordant in three of the nine samples studied. Discordant cases were positive for neoplasia in peripheral blood immunophenotyping, and negative in immunohistochemical analysis of the bone marrow. In these three discordant cases, the tumor cells in the blood sample corresponded to less than 5% of the cellularity of the sample. Conclusion: Even though the use of peripheral blood remains poorly investigated regarding staging and monitoring of NHL, the findings of this study allowed us to define the importance of FCI in the early identification of neoplastic cells in patients with NHL.