[Clinical values of biomarkers in hematopoietic malignancies]

Hematopoietic malignancies include leukemia, lymphoma and multiple myeloma. These diseases are primarily diagnosed on the basis of morphological features of affected cells, which appear in peripheral blood, bone marrow and lymphoid organs. By taking advantage of the repetitive accessibility of the neoplastic cells within the peripheral blood / and/or bone marrow aspirates, morphological tests are conducted not only for diagnosis but also for evaluation of clinical outcomes and prognosis, suggesting that the morphological features are considered as a clinical biomarker in hematopoietic malignancies. However, remarkable progress in molecular targeted therapy and allogeneic hematopoietic stem cell transplantation has improved the long-term prognosis of patients with hematopoietic malignancies, and some patients are curable. Under such modern strategies for therapy, monitoring of minimal residual disease(MRD), which is morphologically undetectable, is required to guide proper management of the disease by evaluation of an optimal response to therapy and early detection of disease relapse. At present, both immunophenotypes(surface markers)and chimeric fusion genes(e. g. BCR-ABL in chronic myeloid leukemia)characteristic of hematopoietic malignant cells are analyzed as clinically useful biomarkers to monitor MRD by two highly sensitive methods, multiparameter flow cytometry and real-time quantitative PCR, respectively. On the other hand, serum markers reflecting the size of the tumor mass are clinically available to monitor the disease progression in mass-forming hematopoietic malignancies: e. g., soluble IL-2 receptor for lymphoma and M-protein or free light chain for multiple myeloma.