[The biology and pathogenesis of multiple myeloma].

Some questions regarding multiple myeloma pathogenesis (MM) still have to be resolved. Various and non univocal mutational events underlie the arising of this disease. These lesions involve various proto-oncogene loci which code for proteins involved in the control of normal cellular growth and differentiation. However, it has not been resolved as to whether the myeloma cells derive from plasma cells which have arisen in response to foreign antigen or if they are autoreactive clone instead. In both cases this clone has an unusual survival potential helped by a defect of the normal regulatory system. Another question is at what level the defect arises in the maturation process which results in the expansion of this clone. Finally, the phenotypic analysis of MM shows surprising data as not only a number of B cell antigens can be seen but also non B cells.