Studying leukemia metastasis and therapy monitoring by in vivo imaging and flow cytometer

Cytotoxic chemotherapy agents are the foundation of current leukemia therapy. For a large number of adult and elderly patients, however, treatment options are poor. These patients may suffer from disease that is resistant to conventional chemotherapy or may not be candidates for curative therapies because of advanced age or poor medical conditions. To control disease in these patients, new therapies must be developed that are selectively targeted to unique characteristics of leukemic cell growth and metastasis. A large body of elegant work in the field of immunology has demonstrated the mechanisms whereby leukocytes traffic to specific sites within the body. Vascular cell adhesion molecules and chemicalattractants combine to direct white blood cells to appropriate environments. Although it has been hypothesized that leukemic white blood cells home to hematopoietic organs using mechanisms similar to those of their benign leukocyte counterparts, detailed study of leukemic cell transit through bone marrow has yet to be undertaken. We develop the "in vivo microscopy" to study the mechanisms that govern leukemic cell spread through the bone marrow microenvironment in vivo in real-time confocal infrared fluorescence imaging. A recently developed "in vivo flow cytometer" and optical imaging are used to assess leukemic cell spreading and the circulation kinetics of leukemic cells. A real- time quantitative monitoring of circulating leukemic cells by the in vivo flow cytometer will be useful to assess the effectiveness of the potential therapeutic interventions.