Protein Expression for Novel Prognostic Markers (Cyclins D1, D2, D3, B1, B2, ITGß7, FGFR3, PAX5) Correlate With Previously Reported Gene Expression Profile Patterns in Plasma Cell Myeloma.

Among plasma cell myeloma (PCM) patients, gene expression profiling (GEP)-based molecular classification has proven to be an independent predictor of survival, after autologous stem cell transplantation. However, GEP has limited routine clinical applicability given its complex methodology, high cost, and limited availability in clinical laboratories. In this study, we have evaluated biomarkers identified from GEP discoveries, utilizing immunohistochemistry (IHC) platform in a cohort of PCM patients. IHC staining for cyclins B1, B2, D1, D2, D3, FGFR3, PAX5, and integrin ß7 (ITGß7) was performed on the bone marrow biopsies of 93 newly diagnosed PCM patients. Expression of FGFR3 was noted in 10 (11%) samples correlating completely with t(4;14)(p16;q32) results (P<0.001); however, the association between FGFR3 and cyclin D2 expression was not significant (P=0.14). ITGß7 expression was present in 9/93 (9%) patients and all these samples also demonstrated upregulated expression of cyclin D2 (P=0.014). Expression of cyclins D1, D2, and D3 was variable in this cohort. Positive protein expression of cyclin D1 was noted in 30/93 (32%), D2 in 17/93 (18%), and D3 in 5/93 (5%) samples. Coexpression of cyclins D1 and D2 was observed in 13/93 (14%) samples, whereas 28 (30%) samples were negative for all the 3 cyclin D proteins. Cyclin B1 was not expressed in any sample, despite adequate staining in positive controls. Cyclin B2 was expressed in 33/93 (35%) and PAX5 protein was noted in 7/93 (8%) samples. In summary, we have demonstrated that mRNA-based prognostic markers can be detected by routine IHC in decalcified bone marrow samples. This approach may provide a useful tool for the wider adoption of prognostic makers for risk stratification of PCM patients. We anticipate that such an approach might allow patients with high-risk immunoprofiles to be considered for other potential novel therapeutic agents, potentially sparing some patients the toxicity of stem cell transplant.

B-lymphoblastic leukemia/lymphoma: overexpression of nuclear DNA repair protein PARP-1 correlates with antiapoptotic protein Bcl-2 and complex chromosomal abnormalities.

Poly(ADP-ribose) polymerase-1 (PARP-1) and Bcl-2 are emerging as therapeutic targets in various cancers. The former is a DNA repair protein associated with genomic stability and apoptosis, whereas the latter is an antiapoptotic protein having a DNA repair function through inhibition of PARP-1. Because genomic stability is critical for prognosis in B-lymphoblastic leukemia/lymphoma (B-ALL), we studied the expression of PARP-1 and Bcl-2 proteins in patients with B-ALL of different ages and compared the results with cytogenetic data. The PARP-1 protein was overexpressed in about two-thirds (61%) of patients with B-ALL. It had a nuclear location, whereas Bcl-2 protein was cytosolic. Expression of the 2 proteins showed a highly positive correlation (ρ = 0.367; P < .001). Overexpression of PARP-1 correlated with a complex karyotype (P = .030), and this correlation remained significant for coexpression of PARP-1 and Bcl-2 proteins (χ(2) = 7.498; P = .024) as well as after exclusion of pediatric patients (n = 9, P = .042). Overexpression of PARP-1 was not significantly more common in diploid versus aneuploid karyotypes (50% versus 59%, P = .610). The PARP-1 protein showed no correlation with specific chromosomal abnormalities associated with prognosis in B-ALL, as defined by the World Health Organization. In conclusion, high expression of the PARP-1 protein among patients with B-ALL is related to a complex karyotype and Bcl-2 positivity. Although these findings require validation in a larger population, the observations will be valuable in planning therapeutic trials (such as of PARP inhibitors and BH3 mimetics).