Detection and Possible Prognostic Relevance ofp53Gene Mutations in Diffuse Large B-cell Lymphoma. An Analysis of 51 Cases and Review of the Literature

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma. Although the presence of p53 gene mutations has been considered as a bad prognostic feature in DLBCL, its clinical significance is still controversial. The aims of this study were: detect the presence of mutations in exons 5 to 9 of the p53 gene and correlate it to prognosis in DLBCL. Fifty-one DLBCL patients were enrolled in this study. Expression of p53 was evaluated by immunohistochemistry. The screening of p53 mutations was performed using PCR-SSCP methods. Cases showing a mobility shift on SSCP electrophoresis were analyzed by automatic sequencing. We could identify 8 missense mutations in 6 of 48 cases (12.5%). In addition, we found a known polymorphism at codon 213 and 2 instances of silent mutations. Of all mutations/polymorphisms found, 7 (64%) were localized in codons previously described as p53 hot spots in NHL cases. Of the remaining alterations (4 or 36%), 2 mutations were localized in codons previously described as hot spots for p53 in other tumors and 2 (codon 142 of the exon 5 and codon 195 of the exon 6), in codons not described as hot spots for p53 up to now. The presence of missense mutations in exons 5 to 9 of p53 gene had adverse impact on overall survival (P = 0.020). Cox's Regression Model identified that high-risk International Prognostic Index (IPI) and p53 gene mutations have independent negative impact on OS. Therefore, the association of IPI with cellular factors, such as p53 mutation, can be very helpful in deciding when we should indicate more aggressive therapies in patients with DLBCL, to somehow increase the chance of cure in these patients.

Plasmablastic multiple myeloma is associated with increased vascular endothelial growth factor immunoexpression

The biologic basis of the negative prognosis of plasmablastic myeloma is not fully understood. To determine whether histologically aggressive multiple myeloma (MM) is associated with a more angiogenic marrow environment, bone marrow samples from 50 recently diagnosed MM patients were evaluated. Twelve percent (6/50) of patients presented plasmablastic MM, and this feature correlated with moderate/strong intensity of vascular endothelial growth factor staining of plasma cells (P = 0.036). Although plasmablastic MM was not associated with increasing of microvessel density, this new evidence of increased expression of vascular endothelial growth factor on plasmablasts suggests that the adverse prognosis conferred by plasmablastic disease may be due, at least in part, to secretion of this angiogenic cytokine, also suggesting that the subset of MM patients with plasmablastic features may derive particular benefit from antiangiogenic therapies.