Prognostic relevance of pretreatment proliferative rapidity of marrow blast cells in childhood acute lymphoblastic leukaemia

Analysis of Argyrophilic Nucleolar Organizer Regions (AgNORs) in Acute Leukemia in Adults

The evaluation of argyrophilic nucleolar organizer regions (AgNORs) uses a simple method used in research into neoplasm. Bone marrow aspirates from 70 patients with acute leukemia underwent morphological, immunophenotypic, and genetic assessment and were stained with silver nitrate. In leukemic cells, the mean AgNORs number, mean AgNORs area, and mean AgNOR-area-to-nucleus-area ratio were calculated in patients with acute myeloid leukemia (AML), patients with acute lymphoblastic leukemia (ALL), and selected risk groups. A higher value of all measured AgNOR parameters was observed in patients with AML compared to the ALL group. In AML patients, a higher mean AgNOR area was found in the ELN3 cytogenetic group compared to the ELN2 cytogenetic group. A higher value of the mean AgNOR count was observed in patients with white blood cells (WBCs) > 12 × 109/L than in the group with WBCs ≤ 12 × 109/L, as well as in patients with >20% blasts in peripheral blood (PB) than in patients with ≤20% blasts in PB. In the ALL group, a higher mean AgNOR-area-to-nucleus-area ratio was found in group with the presence of Philadelphia chromosome Ph(+) than without the Philadelphia chromosome Ph(−). AgNOR parameter analysis is a valuable method for differentiation of AML and ALL in adults.

AgNOR patterns and configurations in adult acute leukemia patients

The number of argyrophilic nucleolus organizer regions (AgNOR) is related to the proliferative activity of cells and the degree of neoplastic transformation. The surface area of AgNOR depending on nuclear structure may be a predictor of tumor recurrence, while research into acute leukemias is scarce. The aim of the study was to determine whether the assessment of AgNOR parameters is useful in the differentiation of acute leukemias and, together with cytogenetic changes, would allow for a quick evaluation of the risk group. The AgNOR structures were analyzed in terms of the shape, surface area and distribution in bone marrow blast cells in patients with acute leukemias. We observed significant differences in the AgNOR structures, simple, compound and complex patterns between acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Complex structures were more numerous in ALL than in AML patients. There were significant differences in the distribution of AgNOR configuration among various cytogenetic AML risk groups. We observed a significant difference in the mean number of AgNOR between ALL-T and ALL-B. We detected diversity in the AgNOR structures and pattern map in AML and ALL. Thus, presentation of a variety of AgNOR configurations is innovative and can be a useful method of differentiating patients with acute leukemia types and cytogenetic risk.

Mitosis-targeted anti-cancer therapies: where they stand

The strategy of clinically targeting cancerous cells at their most vulnerable state during mitosis has instigated numerous studies into the mitotic cell death (MCD) pathway. As the hallmark of cancer revolves around cell-cycle deregulation, it is not surprising that antimitotic therapies are effective against the abnormal proliferation of transformed cells. Moreover, these antimitotic drugs are also highly selective and sensitive. Despite the robust rate of discovery and the development of mitosis-selective inhibitors, the unpredictable complexities of the human body's response to these drugs still herald the biggest challenge towards clinical success. Undoubtedly, the need to bridge the gap between promising preclinical trials and effective translational bedside treatment prompts further investigations towards mapping out the mechanistic pathways of MCD, understanding how these drugs work as medicine in the body and more comprehensive target validations. In this review, current antimitotic agents are summarized with particular emphasis on the evaluation of their clinical efficacy as well as their limitations. In addition, we discuss the basis behind the lack of activity of these inhibitors in human trials and the potential and future directions of mitotic anticancer strategies.

The importance of nucleolar organizer regions in pediatric acute lymphoblastic leukemia

The silver-staining of the nucleolar organizer regions (AgNORs) was performed in patients with acute lymphoblastic leukemia (ALL) to verify the role of cell proliferation in predicting complete remission and survival. Bone-marrow aspiration smears of 20 pediatric cases with ALL, were stained with argyrophilic method during the diagnosis, remission, and 3rd, 6th, 9th, and 12th months after remission. The mean NORs count (NORsc) and the mean of (nucleolar organizer regions surface/total nuclear surface x 100) value (NORss/TNs) for each case were calculated. At diagnosis, the NORsc and NORss/TNs value for the whole series were 3.30+/-0.86 and 4.77+/-1.15, respectively. In complete remission, NORsc and NORss/TNs values were 1.23+/-0.20 and 3.45+/-0.87, respectively, and the differences were statistically highly significant (p < .001). The most important parameters of prognostic factors that effect diagnosis NORss/TNs and NORsc values were found to be FAB morphology and leukocyte count according to the multivariant analysis test. AgNORs analysis is a suitable method to assess cell proliferation in bone marrow aspirate and can predict complete remission, remission duration, and survival in pediatric ALL patients.

Raised blast glutathione levels are associated with an increased risk of relapse in childhood acute lymphocytic leukemia

A preliminary study has linked raised blast glutathione levels with chemoresistance in acute myeloid and lymphoblastic leukemia in adults and children. In this study, therefore, the relationship between leukemic blast glutathione levels and prognosis in childhood acute lymphoblastic leukemia (ALL) was investigated. A total of 77 childhood ALL samples were analyzed, 62 at initial presentation and 15 at relapse. A 20-fold interindividual variation in glutathione levels at presentation (median, 6.54 nmol/mg protein; range, 1.37 to 27.9) was demonstrated. The median level in T-lineage ALL was 2. 3-fold higher than in B-lineage ALL (Mann-Whitney test, P <.0001). There was a significant correlation between presenting white cell count (WBC) and glutathione level (Spearman rank correlation coefficient, rho = 0.45, P =.001). A high DNA index correlated with low glutathione levels (Mann-Whitney test, P =.013). There was no significant relationship between glutathione levels and in vitro drug sensitivity. Patients with glutathione levels above the median had a significantly greater risk of relapse (log-rank test statistic, 5.55; P =.018), and the overall survival rate was significantly reduced (log-rank test statistic, 4.38; P =.04). Multivariate analysis demonstrated that glutathione concentration was of independent prognostic value when assessed in conjunction with age, gender, WBC, and immunophenotype. The association of elevated blast glutathione levels with an increased risk of relapse suggests that glutathione-depleting agents may be of therapeutic value in patients who present with a high WBC.

Nucleolus organizer regions (AgNORs) and total tumor mass are independent prognostic parameters for treatment-free period in chronic lymphocytic leukemia

The aim of our study was to evaluate whether the nucleolus organizer regions (AgNOR) of circulating lymphocytes in chronic lymphocytic leukemia (CLL) could predict the duration of the stable phase (treatment-free period) of this disease. Age, sex, peripheral lymphoctes, hemoglobin, platelet count, Binet's stage, total tumor mass (TTM) and AgNOR pattern at diagnosis were assessed in 57 patients and compared with the time from diagnosis until patients fulfilled the criteria to start chemotherapy. In univariate Cox regression, Binet's stage, hemoglobin, number of peripheral lymphocytes, TTM and the percentage of lymphocytes containing one AgNOR cluster (circulating proliferative fraction) had predictive value. In the multivariate Cox model, only TTM and the percentage of cells with one AgNOR cluster were independent factors predicting the duration of the stable phase. Repetition of these analyses in 500 data sets created by bootstrap resampling confirmed the results. Summing up the percentage of lymphocytes with an AgNOR cluster and the TTM value, a simple prognostic index could be created to give information about the duration of the stable phase in CLL.

Nucleolar size indicates the rapidity of cell proliferation in cancer tissues

In order to define the importance of the nucleolus in tumour pathology, the relationship between nucleolar size and function and tumour mass growth rate was studied in vivo. Ten established human cancer cell lines from colon carcinomas and neuroblastomas were inoculated subcutaneously in athymic mice and the doubling time (DT) of the xenograft tumour mass was calculated. The tumour DTs ranged from 3.2 to 15.7 days. Nucleolar size was evaluated in sections from formalin-fixed and paraffin-embedded tumour samples after silver staining for AgNOR proteins, using a specific image analysis system. The nucleolar area values were inversely related to the xenograft tumour mass DTs (r=-0.90; p<0.001). Nucleolar functional activity was also evaluated using rapid, intermediate, and slow growing tumours (one each). The values of RNA polymerase I activity measured in vitro were strongly related to the corresponding tumour DTs (r=-0. 99; p=0.03). The labelling indices (LIs) of three proliferation markers, MIB1, PCNA, and bromodeoxyuridine (BrdU), were also evaluated. As revealed by the MIB1 and PCNA LIs, almost all the cells of the xenograft tumours were cycling (86.6+/-5.6 SD and 95. 5+/-2.0 SD, respectively). Neither the MIB1, PCNA or BrdU LIs were related to the xenograft tumour mass DT, showing that the different growth rates of tumour xenografts were not due to different growth fractions, but were mainly related to different cell proliferation rates. The present data demonstrate that the size and function of the nucleolus are related to the cell proliferation rate of cancer tissue. Evaluation of nucleolar size after silver staining of AgNOR proteins represents a unique parameter for the histological assessment of rapidity of cell proliferation in tumour lesions.

Levels of expression of CAF7 (CD98) have prognostic significance in adult acute leukemia

The levels of CD98 antigen expression were studied in 62 consecutive cases of adult acute leukemia including 24 acute lymphoblastic leukemia (ALL) and 38 acute myeloid leukemia (AML) using the monoclonal antibody CAF7 and flow cytometry. The mean follow-up was 13.5 months. The mean relative fluorescence intensity (MIF) of CAF7 varied between 6 and 83 channels (256 channels resolution). No correlation was established between CAF7 cell surface density and most of the predictive parameters such as age, sex, blood counts, immunophenotype, proliferative index (PI) or DNA index. Nevertheless expression of CAF7 correlated positively with survival duration (mean 210 vs 391 days, P = 0.048) and complete remission (CR) duration (mean 132 vs 361, days P = 0.032). The levels of CAF7 differed significantly between ALL and AML (P < 0.001), the ALL cases being all CAF7intermediate or CAF7high. In the AML group the low levels of CAF7 expression correlated with shorter CR duration (mean 132 vs 414 days, P = 0.017). The lack of correlation with other clinical and biological parameters suggested that CAF7 might have an independent prognostic significance in adult AML. Although PI was also positively related to survival duration (P = 0.02), it did not correlate with CR duration or the expression of CAF7. We suppose that the prognostic impact of CD98 is related to the control of cell growth and survival in which the molecule normally participates.

N-myc amplification and cell proliferation rate in human neuroblastoma

In neuroblastoma, N-myc amplification has been found to be strikingly associated with rapid tumour progression and poor prognosis. Recent studies have demonstrated that cell proliferative activity also significantly predicts the clinical outcome in patients with neuroblastoma. In order to define the correlation between N-myc amplification and cell proliferation rate, in the present investigation the two parameters were first assessed in 48 neuroblastoma tumours. N-myc amplification was evaluated in frozen specimens by Southern-blot analysis using the NB 19-21 probe and it was detected in nine patients. Cell proliferative activity was determined by measuring the AgNOR protein area in histological sections selectively stained by silver. The mean AgNOR protein area value of neuroblastomas with N-myc amplification (3.63 +/- 1.62 microns2) was not significantly different from that of neuroblastomas without N-myc amplification (2.46 +/- 1.57 microns2; P = 0.30). On the other hand, both N-myc amplification and AgNOR protein expression were found to be significantly related to the clinical outcome of the disease (P < 0.001 and P = 0.0143, respectively; median follow-up time = 47 months; range 18-106 months). In a second set of experiments, the relationship between N-myc amplification and cell proliferation rate was assessed in seven established human neuroblastoma cell lines. N-myc amplification was found to be completely independent of the population doubling time (DT), which, on the contrary, was strictly related to the quantitative expression of AgNOR protein (r = -0.947; P < 0.001). Altogether, the present results indicate that N-myc amplification and cell proliferation rate are not interrelated in neuroblastoma, each representing an independent biological parameter of cancer cells associated with the clinical behaviour of the disease.

Silver-stained nucleolar organizer regions in adenocarcinoma of the cervix--a light and electron microscopic study

An increase in the number of Ag-NORs has been described as a possible marker for histopathological cancer diagnosis. The ultrastructural correlation of the reaction, however, has never been elucidated. In tissue samples of the endocervix of the uterus, we compared the ultrastructural configuration of Ag-NORs with the number of Ag-NORs dots. Light microscopic studies showed that the number of Ag-NORs in adenocarcinoma cells significantly increased, but the relation to the bromodeoxyuridine labeling index was not determined. By electron microscopy, Ag-NORs were only observed in the nucleoli and the nuclear bodies of nuclei. Ag-NORs were localized on all components of the nucleolar structure, but the dense fibrillar component was the predominant site in several cases. The nuclear bodies were exclusively found in adenocarcinoma cells and were argyrophilic. A spotted distribution of Ag-NORs was often found in the nucleoli of adenocarcinoma cells that showed an increased Ag-NOR count. The number of Ag-NORs was attributed not only to the number of nucleoli and nuclear bodies in a nucleus but also to the speckled distribution of silver deposits in a nucleolus. These results imply that the Ag-NOR count is a more definitive indicator of a hyperactive state of the cells than the combined number of nucleoli and nuclear bodies in adenocarcinoma of the uterine cervix.

Argyrophilic nuclear organizer regions (AgNORs) in pediatric acute lymphoblastic leukemia

Nuclear organizer regions (NORs) code for ribosomal RNA and are associated with non-histone nucleoproteins which can be identified by silver staining (AgNORs). AgNORs have been correlated to proliferative activity of tumors and hence may be prognosis-related. The present study evaluates the possible prognostic importance of the AgNORs in tumor cells of patients with pediatric acute lymphoblastic leukemia (ALL). A significant increase in AgNOR counts was observed in ALL patients as compared to normal controls. Further, a significant positive correlation was observed between AgNOR counts and total WBC count at diagnosis. A negative correlation was also observed between AgNOR counts and age of the patients. Logistic regression analysis revealed further correlation between AgNOR counts and disease with an odds ratio of 1.29 (P = 0.03) as compared to normal controls. These results therefore suggest that AgNOR counts may be significant in the evaluation of pediatric ALL.

Levels of CAF7 (CD98) expression correlate with the complete remission duration in childhood acute leukemia

The levels of expression of the activation antigen CD98 were studied by mAB CAF7 in 51 newly diagnosed consecutive cases of childhood acute lymphoblastic leukemia aged from 1 to 13 years. The mean follow-up was 8 months. A wide range of CAF7 expression was observed, the highest mean fluorescence intensity exceeding the lowest by 20 times. No correlation was revealed between CAF7 cell surface density on the one hand and sex, age, WBC, platelet count, LDH level, FAB groups and immunophenotypes on the other. A positive association between the levels of CAF7 expression and the complete remission (CR) duration was observed. The group of CAF7(low) patients had a significantly shorter CR duration compared to the CAF7(intermediate) and CAF7(high) cases (P=0.0099). Half of the CAF7(low) patients did not respond to the induction therapy and failed to achieve remission. These correlations were clearly marked in common ALL (cALL), which was usually considered to have a favorable outcome. All CAF7(low) cALL cases had a significantly shorter CR duration (P=0.027). Thus CAF7 appears to provide additional information on the biological characteristics of childhood ALL and may have prognostic value regarding the response to therapy and remission duration.