Analysis of Bone Tissue Condition in Patients with Diffuse Large B-Cell Lymphoma without Bone Marrow Involvement.

We studied changes in the bone tissue in patients with diffuse large B-cell lymphoma at the onset of the disease (N=41; before chemotherapy) and 5-16 years after the end of treatment (N=47). Osteodensitometry, biochemical markers of osteoporosis in the blood and urine, and gene expression in multipotent mesenchymal stromal cells were analyzed. In multipotent mesenchymal stromal cells of all patients, the expression of genes associated with bone and cartilage differentiation (FGF2, FGFR1, FGFR2, BGLAP, SPP1, TGFB1, and SOX9) was changed. In primary patients, the ratio of deoxypyridinoline/creatinine in the urine and blood level of β-cross-laps were increased, while plasma concentration of vitamin D was reduced, which indicates activation of bone resorption. No differences between the groups were revealed by osteodensitometry. No direct relationship between changes in gene expression in multipotent mesenchymal stromal cells and osteoporosis markers was found. The presence of a tumor in the body affects the bone marrow stroma, but achievement of remission and compensatory mechanisms provide age-appropriate condition of the bone tissue.