AgNORs and myeloma prognosis

AgNOR clusters as a parameter of cell kinetics in chronic lymphocytic leukaemia

Aims-To study correlations between the pattern of silver stained nucleolar organiser regions (AgNORs) in chronic lymphocytic leukaemia (CLL) and parameters of tumour kinetics. To investigate whether quantitation of the AgNOR pattern can be used to discriminate between patients with stable and progressive disease.Methods-Peripheral blood smears from 48 patients with CLL, classified as having either stable or progressive disease (Rai stage III or IV; bulky lymph nodes or massive splenomegaly; or peripheral lymphocytes >100 x 10(9)/1), were studied. For each patient, total tumour mass (TTM) and for patients undergoing a period of observation without treatment, the TTM duplication time (DT) and the lymphocyte doubling time (LDT) were calculated.Results-Four cell types could be distinguished according to their AgNOR pattern: (1) cells with a single cluster; (2) cells with a single compact nucleolus; (3) cells with two compact nucleoli; and (4) cells with several scattered dots. The percentage of cells with clusters was the AgNOR parameter which correlated best with TTM and LDT. Correlations were also seen between the proportion of cells with clusters and age and haemoglobin concentration. A significant correlation with DT could be detected only when age was kept constant. Linear discriminant analysis revealed that the percentage of cells with clusters was the most important prognostic factor. This alone classified 94% of the patients correctly (jackknive procedure) as either stable or progressive CLL.Conclusions-The percentage of circulating lymphocytes with clusters of AgNORs can be used as a parameter of tumour kinetics in CLL and helps to discriminate between patients with stable and progressive disease. For practical purposes, a value of more than 13% of cells with clusters is suggestive of progressive disease.

Interphase ribosomal RNA cistron staining in chronic myeloid leukaemia

Aim-To evaluate the haemopoietic function of bone marrow blood forming cells in human chronic myeloid leukaemia (CML) by means of silver staining of nucleolar organiser region (AgNOR).Methods-Nucleoli were investigated in bone marrow blast cells and in erythroid, granulocytic, and megakaryocytic cells from 10 haematologically healthy subjects and from 26 patients with chronic myeloid leukemia (17 in benign phase, nine with blast crisis). The investigation was done before treatment, by means of a one step silver staining method. In every case 50 to 100 blasts, promyelocytes, myelocytes, immature (pronormoblastic and basophilic normoblastic) and mature (polychromatic normoblastic) erythroid elements, and megakaryocytes were evaluated for the mean numbers of nucleoli and for the average number of AgNORs per nucleus. Student's t test was used to compare the patient and control groups. Other statistical analyses were carried out by means of the computer assisted "HEMA" system.Results-Compared with controls, activation of NORs was noticed only in CML blasts, while there was a decrease in NORs in the erythroid elements, promyelocytes, and megakaryocytes. The AgNOR score of polychromatic normoblasts and megakaryocytes started to decrease in the benign stage of CML, whereas a similar decrease in pronormoblasts, basophilic normoblasts, and promyelocytes was detected only in patients with CML blast crisis.Conclusions-The loss of AgNOR sites in cell series in CML may be related to intrinsic defects in their proliferation.

Use of a complex approach for assessment of metamizole sodium and acetylsalicylic acid toxicity, genotoxicity and cytotoxicity

A complex approach based on the use of test organisms belonging to different systematic groups (plants, invertebrates and vertebrates), as well as the nucleolar biomarker and the micronucleus test on their cells, was applied to assess the toxicity, cytotoxicity and genotoxicity of two pharmaceutical substances (metamizole sodium and acetylsalicylic acid) applied at ic(50) concentrations for mammalian cells. The compound acetylsalicylic acid was evaluated at a concentration (1.6 x 10(3) mg l(-1)) that was non-toxic for bioassays based on fish (Carassius auratus gibelio) and hydra (Hydra attenuata) and acutely toxic for bioassays with ceriodaphnia (Ceriodaphnia affinis) and onion (Allium cepa). The metamizole sodium solution (6.25%) demonstrated acute toxicity for the whole set of test organisms. Both drugs, after their 30-360 min influence on the test organisms, first changed the nucleolar size in plant and animal cells (i.e. the transcriptional activity of ribosomal genes was affected most significantly). Moreover, the metamizole sodium solution caused nucleolar structural damage in 90% of hydra cells as early as after 30 min of exposure. The acetylsalicylic acid solution inhibited essentially the rate of cell division in the meristem of onion roots (the mitotic index decreased to 9.6 per thousand, as compared 51.7 per thousand for the control). The carp incubation and the onion germination in the acetylsalicylic acid solution showed a reproducible increase in the frequency of cells with micronuclei (2 and 5.5 times, respectively) and double nuclei (3 and 1.5 times, respectively). The approach described herein may be applied for obtaining rapid, cost-efficient and useful supplementary data on different types of toxicity for marketed drugs as well as for drugs under development.

A novel nucleolar biomarker in plant and animal cells for assessment of substance cytotoxicity

The cytotoxicity of three substances (mercury(II), metolachlor, and 4-nitroquinoline-N-oxide) was assessed with a set of nucleolar parameters: the average number of nucleoli, the average volume of a single nucleolus, and the proportion of cells with heteromorphic-paired nucleoli (PNhet). Their toxic impact was studied on cells of animal and plant test organisms: onion (Allium cepa), lettuce (Lactuca sativa), and hydra (Hydra attenuata). In general, at concentrations near IC/LC(50) the three chemicals produced similar cytogenetic effects after 30-360 min of contact. For instance, in plant cells (Allium cepa and Lactuca sativa) the toxicants increased the percentage of cells with PNhet, decreased the volume of single nucleoli, and exerted no significant impact on the nucleolar number. In animal cells (Hydra attenuata), they reduced the size of nucleoli, produced no effect on the number of nucleoli, but decreased the share of cells with PNhet. Also, the chemicals affected the cells of the three test organisms to different degrees. Thus, the effectiveness of our approach of using nucleolar biomarker (use of the proposed set of parameters and time schedule of several determinations in the first hours of toxicant contact, etc.) as a means of assessing cytotoxicity was confirmed.

Prognostic relevance of AgNORs in tumor pathology

The importance of the analysis of the silver-stained nucleolar organizer regions (AgNORs) for prognostic purposes in tumor pathology has been reviewed. Current available data from the literature demonstrate that the evaluation of the quantity of interphase AgNORs is an independent prognostic factor in several types of human tumors. Results of our investigations indicate that AgNORs are the most powerful variable predicting survival in patients with pharyngeal carcinoma, multiple myeloma, male breast and prostate carcinoma. The combination of AgNOR counts and histologic pattern allows the stratification of patients with multiple myeloma, pharyngeal and prostate carcinoma into low- and high-risk groups, which could benefit from different therapy. Moreover, AgNOR analysis predicts response to treatment in adult patients with acute myelogenous leukemia, and appears as an independent prognostic factor in a prospective study on renal cell carcinoma. Therefore, AgNOR analysis is a really important prognostic factor for several human neoplasias. The experimental and theoretical justifications for AgNORs as a prognostic factor are also reviewed, in particular the strict correlation between AgNOR quantity and tumor cell doubling time. Lastly, the lack of prognostic significance of AgNOR analysis in some circumstances is critically discussed.

Risk groups of myeloma patients by histologic pattern and proliferative activity

We investigated the histologic pattern and the cell proliferative activity of myeloma cells by the analysis of the nucleolar organizer regions (AgNORs) in bone marrow biopsy specimens from 150 multiple myelomas at diagnosis. The objective was an attempt to define risk groups of myeloma patients. On univariate analysis, the percentage of bone marrow plasma cells (BMPC%), the pattern of infiltration, the degree of plasma cell (PC) atypia, the marrow fibrosis, and the number of AgNOR/PC were correlated with survival time. On multivariate analysis, only AgNOR counts and pattern of infiltration retained independent prognostic significance. At 4-year followup, all patients with BMPC% < or = 20, interstitial pattern of invasion, and well-differentiated (G1) PC plus AgNOR/cell < or = 3.32 were alive, while no patient with BMPC% >50, diffuse pattern of infiltration, and poorly differentiated (G3) PC plus AgNOR/cell >5.15 survived (p < 0.0001). In conclusion, the histologic pattern and proliferative activity of myeloma cells, evaluated by AgNOR counts, are reliable predictors of survival in myeloma. Both parameters can be easily assessed in the same biopsy specimen, are reproducible, and permit identification of a group of patients with favourable outcome at 4-year followup. Thus, bone marrow biopsy should always be included in the diagnostic procedures for myeloma patients.

Correlation between argyrophilic nucleolar organizer region counts and labelling index in multiple myeloma

The correlation between the bromodeoxiuridine (BrdU)-labelling index (LI) of plasma cells and a new proliferation marker, the Argyrophilic Nucleolar Organizer Regions (AgNORs), was investigated in 44 myeloma patients at diagnosis. A preliminary analysis was made to verify the reproducibility of the assessment of plasma cell infiltration (PC%) in bone marrow aspirates, used to collect cells for LI determination, and in bone marrow biopsies, used for AgNORs evaluation. Although an overall good correlation was observed between PC% in biopsies and aspirates (r=0.58, p=0.001), the ratio between PC% in biopsies and in aspirates ranged form 0.35 to 7.5. Only 17 patients (38.6%) were within the 0.5-1.5 range. A positive correlation between LI and AgNORs was observed in these patients (r=0.68, p=0.003), whereas the correlation was lost in patients with higher ratio between PC% in biopsies and in aspirates (r=0.08, p=0.69). The prognostic significance of AgNORs was confirmed by survival analysis, showing a reduced survival for patients with high (>4.4) AgNOR counts (14 months vs 35 months, p=0.004). The AgNORs analysis therefore allows the simultaneous evaluation of myeloma cell infiltration, degree of differentiation and kinetics of growth in bone marrow biopsies. AgNOR counts deserve to be included in the procedures for diagnosis and prognostic evaluation of myeloma patients.