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Introduction: Significant and accessible predictive factors for bortezomib treatment in plasma cell myeloma (PCM) are still lacking. TP53 codon 72 polymorphism (P72R) results in proline (P) or arginine (R) at 72 amino acid position, which causes synthesis of proteins with distinct functions. The aims of our study were to: 1) analyze whether this polymorphism is associated with an increased risk of PCM; 2) study whether the P72R polymorphism affects overall survival (OS) among PCM patients; 3) assess the possible association of the P72R polymorphism with sensitivity to bortezomib in cell cultures derived from PCM patients., Material and Methods: Genomic DNA from newly diagnosed 59 patients (without IgVH gene rearrangements and TP53 deletions) and 50 healthy blood donors were analyzed by RFLP-PCR to identify TP53 polymorphism. Chromosomal aberrations were detected by use of cIg-FISH. The lymphocyte cell cultures from a subgroup of 40 PCM patients were treated with bortezomib (1, 2 and 4 nM)., Results: The P allele of the P72R polymorphism was more common than the R allele in PMC patients compared to controls (39% vs. 24%), and the difference was significant (p = 0.02). The PP and PR genotypes (in combina-tion) were more frequent among cases than in controls (65% vs. 42%, OR = 2.32, p = 0.04). At the cell culture level and 2 nM bortezomib concentration the PP genotype was associated with higher necrosis rates (10.5%) compared to the PR genotype (5.7%, p = 0.006) or the RR genotype (6.3%, p = 0.02); however, no effect of genotypes was observed at bortezomib concentrations of 1 and 4 nM. The shortest OS (12 months) was observed in patients with the PP genotype compared to patients with the PR or RR genotypes (20 months) (p = 0.04)., Conclusions: The results suggest that P72R polymorphisms may be associated with an increased PCM risk and may affect OS of PCM patients. However, we saw no consistent results of the polymorphism effect on apoptosis and necrosis in cell cultures derived from PCM patients. Further studies are need in this regard.

Recent studies have been carried out to delineate further the role of the Rb1 gene in B-cell chronic lymphocytic leukaemia (B-CLL). The suggested role of the Rb1 gene in this disease was based on cytogenetic data. CLL patients (40 in toto) were examined using cytogenetic and molecular biological methods. R-banding analysis of metaphase chromosomes revealed aberrations in only seven cases containing either the Rb1 gene or a chromosome 13 monosomy. No evident differences were found by RT-PCR analysis of Rb1 gene expression. The amounts of the RT-PCR products obtained appeared to be approximately equal in all cases, and was independent of the clinical stage, immunophenotypes and LPS or TPA stimulation.

The in vitro production and secretion of the immunoglobulins IgM, IgG, Kappa and lambda light chains by peripheral blood lymphocytes from chronic lymphocytic leukaemia patients was examined. The ELISA system was employed to quantitate the immunoglobulins secreted in the culture supernatants. Lipopolysaccharide and phorbol esters with CA++ ionophore were used as lymphocyte stimulators. The maturation of cultured lymphocytes was demonstrated by synthesis of cytoplasmic immunoglobulins and Ig secretions typical for plasma cells. In one case an isotype switch C mu for C gamma was observed.

Lipopolysaccharide (LPS) and phorbol esters (TPA) stimulate lymphocytes proliferation in two different ways. While LPS primary function is specific receptor binding, TPA directly activate cellular protein kinase C. The stimulation of human leukaemic lymphocytes (from chronic lymphocytic leukaemia patients) with LPS and TPA results in two different types of response: to both stimulators, and to LPS only. Therefore the supposed defect of cellular receptors can not explain all the observed effects. The existence of TPA independent second messengers and changes in signal transduction pathways downstream of PKC can be considered.