[The plasma cell myeloma--molecular pathogenesis and target therapies].
The cells of the malignant clone of plasmacell myeloma have cytogenetic aberrations in a substantial number of cases. Many of these abnormal karyotypes are predictive for an unfavorable outcome. Gene mutations and abnormal gene expression, particularly of oncogenes and tumor suppressor genes, are often observed in myeloma cells. The cross talk between the myeloma cells and the bone marrow microenvironment plays an important role for growth and survival of the tumor cells. As a consequence of this cell-to-cell-interaction, several cytokines are secreted. The intracellular signaling, evoked by these cytokines, leads to continuous growth and proliferation and inhibition of apoptosis. Since these molecular pathways have been defined, many new targets for therapeutical interventions become obvious. Some molecules, directed against cytokines, are under early clinical investigation. Medicaments intervening in the cross talk between the myeloma cell and the bone marrow stroma as Thalidomide, Lenalidomide or Bortezomib are already available. Many of the myeloma patients suffer from bone disease. Some new drugs inhibiting the differentiation and activation of osteoclasts are evaluated in clinical trials. These molecules will be an important contribution against the painful bone disease of plasmacell myeloma.