RESUMEN
Background Immunofluorescence techniques done on formalin-fixed, paraffin-embedded tissue can serve as salvage techniques in cases where immunofluorescence on the frozen section may not be adequate or available. The present study was undertaken to assess the diagnostic utility of paraffin immunofluorescence by proteinase K digestion on renal biopsy compared to fresh frozen immunofluorescence. Methodology The paraffin immunofluorescence by proteinase K digestion of paraffin-embedded renal biopsy (IF-FFPE) was standardized and compared with the immunofluorescence on fresh frozen tissue (IF-Frozen). A total of 50 cases of the native renal biopsy were included in the study, and their intensity for fluorescein isothiocyanate-labeled IgA, IgG, IgM, C3, kappa, and lambda was compared. Results A total of 50 cases of the native renal biopsy were included in the study, and their intensity for fluorescein isothiocyanate-labeled antibodies of IgA, IgG, IgM, C3, kappa, and lambda was compared. The difference of 2+ intensity of antibodies between IF-FFPE and IF-Frozen was noted mainly in lupus nephritis (15%), followed by IgA nephropathy (10%) and membranoproliferative glomerulonephritis (7%). IF-FFPE showed a sensitivity of 90.3%, 91.8%, 82.7%, 81.1%, 92.1%, and 94.6% for IgA, IgG, IgM, C3, kappa, and lambda, respectively, whereas specificity was 100% for IgA, IgG, C3, kappa, and lambda and 95.2% for IgM. Conclusions Immunofluorescence techniques done on formalin-fixed, paraffin-embedded tissue can serve as salvage techniques in kidney biopsies.
RESUMEN
BACKGROUND: Poly-ADP-ribosylation, a reversible post-translational modification of primarily chromosomal proteins, is involved in various cellular and molecular processes including carcinogenesis. ADP-ribose polymer or poly-ADP-ribose adducts are enzymatically added onto or stripped off the target chromosomal proteins during this metabolic process. Due to this, the chromatin superstructure is reversibly altered, which significantly influences the pattern of gene expression. We hypothesize that a decrease in the concentration of total poly-ADP-ribose adducts of peripheral blood lymphocyte (PBL) proteins strongly correlates with the incidence of human cancer. RESULTS: Using a novel immunoprobe assay, we show a statistically significant (P ≤ 0.001) reduction (~ 42 to 49%) in the level of poly-ADP-ribose adducts of PBL proteins of patients with advanced cancers of head & neck (H & N) region (comprising fourteen distinct cancers at different sites), breast and cervix in comparison to healthy controls. CONCLUSIONS: These findings imply potential utility of the poly-ADP-ribose adducts of PBL proteins as a novel and general biomarker of human cancers with potentials of significant clinical and epidemiological applications.