p16 gene methylation lacks correlation with angiogenesis and prognosis in multiple myeloma.

Methylation of p16 gene is a relatively frequent molecular finding in multiple myeloma (MM), but its clinical implication is disputable. Cell cycle regulators are now recognized as active in the control of angiogenesis, which is an integral component of pathogenesis and a target for new treatment modalities of this disease. On such background, we focused on determining whether loss of p16 function by methylation could be associated with increased angiogenesis and VEGF expression, and the prognostic relevance of p16 methylation in 50 untreated, newly diagnosed MM patients. Thirty-one percent (13/42) of 42 patients assessable for p16 gene methylation showed to be methylation-positive. High-angiogenesis was present in 73% of cases, but methylation of the p16 gene did not associate with angiogenesis or with VEGF expression. Also, p16 methylation did not show prognostic relevance or correlation with the clinical and laboratory parameters of prognostic significance in univariate analysis. P16 immunoexpression presented only a faint agreement with the molecular study. Therefore, p16 methylation seems to have no correlation with angiogenesis and VEGF expression, neither with overall and event-free survival in MM patients. Besides, P16 immunohistochemistry seems inadequate to substitute the molecular study of methylation in this type of tumor cells. Additional studies are needed to clarify the correspondence between the epigenetic alteration of the p16 gene and its protein immunexpression, and the clinical relevance of p16 methylation in MM patients.

Possible influence of clinical stage and type of treatment in the persistence of residual circulating t(14;18)-positive cells in follicular lymphoma patients.

Many patients with follicular lymphoma (FL) achieve response after treatment but complete remission (CR) rates are very low. Thus the majority of them will relapse, mainly those in advanced stage disease, due to the persistence of residual disease. Therefore, this study had the following aims: to determine the presence of bcl-2/IgH rearrangement in peripheral blood of early and advanced stage FL patients after treatment and to correlate it with their clinical situation at the same moment. We obtained 100 consecutive peripheral blood samples from 30 FL cases and conducted molecular studies using two separate semi-nested PCRs for MBR and mcr rearrangements. These semi-nested PCRs for bcl-2/IgH rearrangement were able to detect one positive cell among 10,000 normal cells. Clinical and molecular evolution of patients diagnosed as early stage disease suggested that molecular response could be obtained even with conventional chemotherapy or radiotherapy. In this group of patients, 64% achieved molecular response in some point during follow-up. However, only 23% of patients diagnosed as advanced stage disease reached molecular response when treated with chemotherapy (with or without radiotherapy). Due to the low number of subjects assessed in this study, we only found a tendency to significance when clinical stage at the diagnosis was associated to molecular response (P = 0.095). We observed 100% of concordance between clinical remission and molecular response in patients after bone marrow transplantation or in those cases treated with monoclonal antibody anti-CD20. This retrospective study, performed in a restricted number of patients, suggests that molecular response can be obtained in FL patients diagnosed at early stage disease, even with conventional chemotherapy and radiotherapy. In advanced stage disease, concordance between clinical remission and molecular response was observed in the majority of patients after bone marrow transplantation or in those cases treated with monoclonal antibody anti-CD20. The prognostic significance of this data should be confirmed with extended follow-up and in a larger number of patients.

Comparative expression of a set of genes to an internal housekeeping control in CDNA amplified and not amplified by PolyAPCR in non-Hodgkin's lymphoma samples obtained from fine-needle aspiration cytology.

AIM: We aimed to evaluate the amount and quality of the RNA obtained from lymph nodes of non-Hodgkin lymphomas (NHLs) patients using fine-needle aspiration cytology (FNAC), and to develop strategies to overcome eventual technical drawbacks. MATERIALS AND METHODS: Twenty-six patients with NHL and 10 tonsils from children submitted to tonsillectomy underwent FNAC. The aspirates were performed using both cytoaspirator (sample A) and syringe and needle (sample B). The RNA was extracted using Trizol reagent and transcribed with the Superscript kit (Invitrogen). The quality of RNA was verified through the amplification of a beta-actin 155-bp fragment. RESULTS: Fifty-two NHL and 20 tonsil samples were analyzed. The total amount of RNA in the tonsil samples varied from <1.0 to 6.2 microg with cytoaspirator (A) and from <1.0 to 4.7 microg with syringe and needle (B). The total amount of RNA obtained from NHL varied from <1.0 to 6.5 microg with cytoaspirator (A) and <1.0 to 5.5 microg with syringe and needle. In an attempt to increase the amounts of RNA in each sample, we standardized the polyAPCR technique, which increased by 10 times the amount of cDNA in most of the test and control samples. The efficiency of the reaction was verified through the amplification of beta-actin, in which 100% of the test and control samples were amplified. When polyAPCR cDNA and nonamplified cDNA samples were paired to be evaluated by real-time PCR, using glyceraldehyde-3-phosphate dehydrogenase as the constitutive gene and nuclear factor-kappa B and NFkappaBIA as target genes, there was equivalence in the amplifications of 100% of the 15 evaluated samples. CONCLUSIONS: Our results showed that FNAC, obtained either by cytoaspirator or syringe and needle, is a good source of small amounts of RNA. The polyAPCR technique significantly increased the amount of genomic material, which might be a cDNA source for future gene expression studies.