CD31 density is a novel risk factor for patients with B-cell chronic lymphocytic leukaemia.

CD31 is the physiological ligand for CD38. CD38 expression in a high percentage of malignant cells is a risk factor for patients with B-cell chronic lymphocytic leukaemia (B-CLL). A previous investigation demonstrated that quantification of CD38 improves upon the prognostic value of the percentage expression. A recent study states that the percentage of CD31 expression is not predictive in B-CLL. We reassessed the predictive power of CD31 in a cohort of 120 patients with B-CLL. Peripheral blood cells were stained with PCP-labelled anti (alpha)-CD19, FITC-alpha-CD5 and PE-alpha-CD31 antibodies. CD31 expression was quantified using beads of specific antibody binding capacity and the density was correlated with clinical outcome. End points were disease-specific survival and time to treatment (TTT). We report that CD31 density was significantly lower in the group of patients with Binet stage B and C of disease progression (P=0.0003). There was an inverse, significant correlation between CD31 and CD38 densities (R= -0.281, P=0.002). All CLL-related deaths occurred in patients with low CD31 density. Low CD31 predicted for poor disease outcome (survival, P=0.0087; TTT, P=0.0064) and identified Binet stage A patients (survival, P=0.0350; TTT, P=0.0716) and those with low CD38 (survival: all patients, P<0.0001; stage A, P=0.003) who followed a more aggressive clinical course. Disease-specific survival of patients with low CD31 and high CD38 densities was significantly shorter than all other groups. In addition, low CD31 density was a poor risk factor irrespective of patient age (survival: all patients, P=0.045; stage A, P=0.021) and identified patients with Binet stage B/C as the highest risk group (P<0.0001). In conclusion, low CD31 density is an adverse prognostic indicator in B-CLL. Also, low CD31 density enhances the prognostic power of CD38 density. The interaction between CD31 and CD38 and its clinical significance in B-CLL requires further investigation.

A new subtype-specific monoclonal antibody for IAP-survivin identifies high-risk patients with diffuse large B-cell lymphoma and improves the prognostic value of bcl-2.

Anti-apoptotic factors including IAP-survivin and bcl-2 are involved in carcinogenesis and predict for disease outcome for patients with cancer. We used RT-PCR and specific primers to generate two recombinant IAP-survivin proteins; one encoding for the full-length protein and the second comprising the survivin sequence incorporating amino acids 98 to 142. Both proteins were used to immunize mice and as capture antigens to screen NS1/immune splenocyte hybridoma supernatants for anti-survivin antibody in ELISA assays. The antibody designated F2-9C3 was most effective and reacted with both recombinant proteins and with the native protein present in lysates of A549 (lung carcinoma) and Jurkat cells in Western blots, immunoprecipitation and formalin-fixed tissue sections. Immunohistochemical staining of normal and neoplastic tissues showed association of the F2-9C3 antibody with the mitotic spindles. Expression of survivin was not detected elsewhere in sections of normal tissue while all neoplastic tissues examined, including those from patients with diffuse large B-cell lymphoma (DLBCL), showed significant expression of survivin. The intensity and localization of staining in these tumours varied and was observed in cytoplasm and/or nuclei. High nuclear expression of survivin predicted the disease outcome in patients with DLBCL. This association was evident when relating intensity to patient survival (p=0.0321) and strengthened when a score was calculated based on both staining intensity and the proportion of the reactive tumour cells (p=0.0128; reduction in the mean survival times: 35% and 46%, respectively). Elevated expression of bcl-2 protein also identified the high-risk patients (p=0.0095; reduction in mean survival time: 37%). Over-expression of both factors was a more powerful indicator of poor prognosis than either marker alone (p=0.0054, 70% reduction in mean survival time). In conclusion, our novel F2-9C3 monoclonal antibody is effective in determination of expression of IAP-survivin in neoplastic tissue. Nuclear overexpression of IAP-survivin using this antibody predicts the disease outcome in patients with DLBCL and significantly improves the predictive power of bcl-2 in these patients.

MicroRNAs are suitable for assessment as biomarkers from formalin-fixed paraffin-embedded tissue, and miR-24 represents an appropriate reference microRNA for diffuse large B-cell lymphoma studies.

Tissue biopsy specimens in the form of formalin-fixed paraffin-embedded tissue (FFPET) represent a valuable resource for biomarker identification and validation. However, to date, they remain an underused asset due to uncertainty regarding RNA extraction and the reliability of downstream techniques, including quantitative RT-PCR. Recently, much interest has emerged in the study of microRNAs; small single-stranded RNAs with a role in transcriptional regulation, that are thought to be well preserved in FFPET. In this study, we show that microRNA expression is comparable between FFPET and matched fresh-frozen samples (miR-17-5p: p=0.01, miR-92: p=0.003), and demonstrate that no significant deterioration in expression occurs over prolonged FFPET storage (p=0.06). Furthermore, microRNA expression is equivalent dependant on RNA extraction method (p<0.001) or DNAse treatment of total RNA (p<0.001). Finally, we validate miR-24 as a suitable reference microRNA for diffuse large B-cell lymphoma (DLBCL) FFPET studies.