Chromosomes and causation of human cancer and leukemia. XXXVII. Nucleolus organizers on the Ph1 chromosome in chronic myelocytic leukemia

Ag-NOR staining and satellite association in lymphoproliferative disorders

The nucleolar organizer regions (NORs) activity and the frequency of satellite associations (SA) in peripheral blood lymphocytes from patients with two chronic lymphoproliferative disorders were studied: 10 cases with B-cell chronic lymphocytic leukemia (B-CLL) and 10 with mycosis fungoides (MF). Thirteen healthy individuals formed the MF control group, and the oldest 7 constituted the B-CLL control group. The mean of Ag-NORs per metaphase was increased in B-CLL patients (8.80 +/- 0.63) compared with their controls (7.99 +/- 0.90) (P less than 0.025), meanwhile MF patients' value did not differ from their controls. In both disorders, the frequency of Ag-NORs in the G chromosomes was increased. The analysis of SA in B-CLL patients only revealed an increase in the frequency of cells with more than 4 ASPs (association pairs). Meanwhile, a significant higher mean of ASPs per cell in MF patients (1.74 +/- 0.41) compared to controls (1.40 +/- 0.24) (P less than 0.05) was observed. Furthermore, a close correlation between cells with complexes of 3 or more chromosomes and the mean of ASPs per cell was also found in MF. In conclusion, an increase of the Ag-NORs expression in B-CLL patients and a modification in the degree of SA in MF patients were found.

Age related decrease of NOR activity in bone marrow metaphase chromosomes from healthy individuals

AIMS

To present data obtained from human bone marrow preparations from healthy individual showing that the proportion of metaphases with silver stained nucleolar organiser region (AgNOR) chromosomes is associated with the age of the donor.

METHODS

Bone marrow preparations from eight Russian and 10 Argentinian healthy individuals donating bone marrow for heterologous transplantation were studied by silver staining. The Russian bone marrow preparations were used directly, while the bone marrow specimens from Argentinian donors were incubated for 24 hours at 37 degrees C in F-10 medium with 15% fetal bovine serum. The slides were silver stained by the one step method of Howell and Black with slight modifications. Thirty metaphases with clearly defined D and G group chromosomes were scored for the numbers of AgNORs. All metaphases that were adjacent to silver stained interphase nuclei were analysed to assess the percentage of AgNOR positive mitoses. The Kruskal Wallis test and Kendall's rank correlation coefficient (rK) were used to assess the relation between age and the percentage of AgNOR positive cells.

RESULTS

The mean numbers (SE) of AgNORs per metaphase were 5.06 (0.17) and 5.56 (0.23) for the Russian and Argentinian groups, respectively, with no significant differences between the two groups. The common percentage of AgNOR positive cells decreased significantly as a function of age, with an rK = -0.57 (p < 0.0012).

CONCLUSIONS

The percentages of AgNOR negative metaphases in bone marrow from healthy individuals is strongly associated with age and this may be related to age related telomere loss.

Proliferating cell nuclear antigen (PCNA) and nucleolar organiser regions in Hodgkin's disease: correlation with morphology

AIM

To define the distribution of proliferating cell nuclear antigen (PCNA) and silver staining nucleolar organiser regions (AgNORs) in Hodgkin's disease.

METHODS

PCNA was shown in a series of 34 cases of Hodgkin's disease using immunohistochemical methods. In a second series of 46 cases the AgNOR technique for interphase nucleolar organiser regions was studied. Both series comprised routinely fixed and processed paraffin wax sections of three main Rye subtypes.

RESULTS

In all cases, regardless of Rye subtype, most Sternberg-Reed cells and mononuclear Hodgkin cells showed nuclear PCNA immunoreactivity and such cells had 15 or more AgNOR sites. The Hodgkin cells had, in general, about half the number of AgNORs seen in Sternberg-Reed variants.

CONCLUSIONS

These data support the notion that Hodgkin's disease can be regarded as a high grade lymphoma, the large Hodgkin's and Sternberg-Reed cells being the (PCNA positive and AgNOR rich) neoplastic elements with high proliferative capacity. A smaller proportion of the associated cells also showed evidence of proliferation.

High incidence of ectopic nucleolar organizer regions in human testicular tumors

Eight primary testicular germ cell tumors, one teratocarcinoma cell line, and one Leydig cell tumor were studied to determine the importance of modifications of the nucleolar organizer regions (NORs) in human testicular tumors. Cytogenetic analysis after silver staining showed active ectopic NORs in two primary embryonal carcinomas (EC) in the cell line and in single cells of each of two seminomas (S). In one EC, an ectopic NOR was localized to chromosomal region 1q4; the others were on unidentified rearranged chromosomes. All tumors in which ectopic NORs were observed were hyperdiploid and possessed marker chromosomes typical of human germ cell tumors. Quantitative DNA analysis was performed on three tumors: a teratocarcinoma (TC) and the Leydig cell tumor, which had provided no analyzable mitoses, and a seminoma which was cytogenetically diploid. In all three cases, the major populations were hyperdiploid. The results, in combination with those of an earlier study, provide evidence that active ectopic NORs are common in human testicular tumors.

Variations in the occurrence of silver-staining nucleolar organizer regions (AgNORs) in non-proliferating and proliferating tissues

Previous studies on the subject of silver-staining nucleolar organizer regions (AgNORs) as indicators of precise proliferative status of tissues have sometimes resulted in ambiguity. The studies, however, have most frequently addressed themselves to the prognosis of neoplasias, with the aim of using AgNORs principally to distinguish between benign and malignant tumours. This investigation was to determine a base-line relationship of AgNOR clusters to proliferation and thus concentrated on normally proliferative tissues and conditionally renewing tissues after appropriate stimulation. Two murine transplantable tumours were also examined as examples of frank malignancy. As an example of the former, variations in AgNOR clusters were noted in the small intestine of man, mouse, and rat. The conditionally renewing systems of liver, prostate, and salivary glands were stimulated into proliferation by two-thirds partial hepatectomy, castration followed by treatment with testosterone, and isoproterenol treatment, respectively, in rat models; the murine sarcoma SaF and carcinoma CaNT provided relatively simple malignant tumours for AgNOR investigation. Proliferation was monitored by noting labelling indices after injection with bromodeoxyuridine (BrdUrd) in vivo followed by immunocytochemical visualization of S-phase cells. In all tissues, an increase in the size of AgNOR clusters rather than their number correlated positively with elevated labelling, particularly with the emergence of silver-staining regions of 2-3 microns visible diameter. Thus, increased AgNOR cluster size (diameter) as representative of AgNOR cluster/nucleolus volume was found to be dependent on proliferative activity in a range of normal and neoplastic tissues.

Silver staining of nucleolar organizer regions in malignant melanoma and melanotic nevi

The recently described method of staining nucleolar organizer regions (NOR) with colloidal silver nitrate was applied to the paraffin sections of five junctional nevi, 13 compound nevi, seven Spitz nevi, nine cellular blue nevi, 11 dysplastic nevi, seven malignant lentigines, 12 superficial spreading melanomas, and 14 secondary melanomas. There was a significant difference between the pooled silver-NOR (AgNOR) numbers of the 45 benign lesions (mean, 1.22; SD, 0.51) and the 33 melanomas (mean, 9.18; SD, 4.05) by t test analysis (P less than .01). The difference was striking enough to be recognized on casual microscopic examination, suggesting that AgNOR staining may be a useful technique to help separate melanocytic nevi from malignant melanomas.

Differential nucleolus organizer activity in normal and leukemic bone marrow

A cytochemical technique that uses silver nitrate staining has been used to study the nucleolus organizer activity in bone marrow cells from 13 patients with acute lymphocytic leukemia (ALL), 11 patients with chronic myelogenous leukemia (CML), 7 patients with acute myelogenous leukemia (AML), and 4 healthy persons. Our results indicate that the nucleolus organizer region (NOR) activity was significantly lower in the control group than in the ALL patients. The NOR activity level was significantly lower in both the CML patients in chronic phase and the AML patients than in the ALL group and similar to the control group. These disease-related differences in NOR activity as detected by silver staining can be used as diagnostic procedure in evaluating human leukemias.

Cytogenetic analyses of somatic chromosomes in a transplantable monomyelocytic leukemia in BALB/c mice

In vivo cytogenetic analyses have been performed using G-, C-, and nuclear organizing region (NOR)-banding techniques, and sister chromatid exchanges (SCE) on a transplantable monomyelocytic leukemia (MML) initially induced in female BALB/c mice by the Rauscher leukemia virus (RLV). Centromeric associations have been found to be greatly increased in MML transplanted mice. Transplantability of the disease has been demonstrated at the cytogenetic level by the presence of female cells in males transplanted with MML cells. G-banding analysis has shown the existence of a marker deleted chromosome 18 in all tissues examined (bone marrow, spleen, and peripheral blood) restricted to female transplanted cells. The NOR-banding analysis has shown a slight increase in the number of Ag-NOR sites per metaphase in MML transplanted mice compared with controls and the existence of an extra chromosome having NOR in MML transplanted mice. No differences were found in C banding between controls and MML transplanted mice. In MML transplanted males, female transformed cells showed a significant reduction in SCE frequency compared with host male cells or controls.

Differentiation of malignant from normal and reactive mesothelial cells by the argyrophil technique for nucleolar organiser region associated proteins

Nucleolar organiser regions represent nucleolar activity in both normal and malignant cells. More numerous nucleolar organiser regions have been found in cells from many forms of malignancy than in normal cells. An argyrophilic method of staining these regions (the AgNOR technique) has been applied to specimens of pleura obtained by biopsy or at necropsy in an attempt to differentiate between normal, "reactive," and malignant pleural disease. The number of nucleolar organiser regions in samples taken from 10 patients with normal pleura (mean 1.04 (95% confidence interval 0.96-1.12] was less than the number seen in samples from 10 patients with "reactive" (inflammatory) pleural disease (1.75 (1.34-2.16); p less than 0.001). This is the first demonstration of increased numbers of nucleolar organiser regions in an inflammatory condition. In specimens from 25 patients with mesothelioma the corresponding numbers of nucleolar organiser regions were: tubulopapillary (n = 10) 5.43 (4.42-6.44); undifferentiated (n = 5) 5.00 (3.29-6.71); sarcomatous (n = 5) 7.52 (3.96-11.08); and mixed histological types (n = 5) 4.94 (3.2-6.68). All these values differ significantly from those for both normal and "reactive" tissue (p less than 0.001). It is concluded that the AgNOR technique separates "reactive" pleural disease from mesothelioma with a high degree of confidence and is an important advance in the diagnosis of malignant mesothelioma.

A comparison of nucleolar organizer region staining and Ki-67 immunostaining in non-Hodgkin's lymphoma

Eighty cases of non-Hodgkin's lymphomas were examined independently using the monoclonal antibody Ki-67 and an argyrophilic method for the demonstration of nucleolar organizer regions. The evidence that Ki-67 immunoreactivity may be used as a marker of cell proliferation is described and the nature of nucleolar organizer regions reviewed. The proportion of tumour cells with nuclear Ki-67 immunoreactivity and the mean number of nuclear organizer regions are shown to be linearly related (r = 0.86, P less than 0.001) although some scatter was observed. These data suggest that the mean number of nucleolar organizer regions may reflect the cellular kinetics of a tumour. This study also provides further evidence supporting the thesis that the mean nucleolar organizer region score is related to the histological grade of non-Hodgkin's lymphoma. Ki-67 immunostaining and nucleolar organizer region staining would seem to provide comparable data, at least in non-Hodgkin's lymphoma, but the latter method has the advantage of being applicable to conventionally fixed and processed paraffin sections.

Correlation between DNA flow cytometric and nucleolar organizer region data in non-Hodgkin's lymphomas

The argyrophilic staining (AgNOR) technique, novel in histopathology, was applied to a series of 20 non-Hodgkin's lymphomas (NHL) of established Kiel subtype. The method demonstrates nucleolar organizer regions (NORs) by virtue of sulphydryl groups on their associated proteins and the enumeration of AgNOR foci has been previously shown to discriminate between NHL of low- and high-grade histological types. This finding was confirmed and the results were compared with those obtained by means of DNA flow cytometry performed on paraffin wax-embedded tissue from the same lymphomas. There was a very good linear correlation between the mean numbers of AgNOR sites per nucleus and the percentage of S-phase cells for each case, both values being high in high-grade NHL and low in low-grade lesions. Conversely there was no significant correlation between the DNA index, representing DNA aneuploidy, and AgNOR counts. It is suggested that the numbers of AgNORs in a lymphoma may be related to the dividing fraction of cells rather than, as might be expected, to ploidy alone. It is also proposed that the AgNOR technique, which is rapid, simple, and inexpensive, may provide, at least, an adjunct to DNA flow cytometry in the assessment of neoplasm in histopathology.

Silver bands in chronic granulocytic leukemia. II. The Philadelphia chromosome

To test if rRNA gene activity in the Philadelphia (Ph) chromosome nucleolar organizing regions (NOR) differs from other NOR we scored silver banding patterns in leukemic cells of 32 patients (one patient was sampled twice) in the chronic phase of chronic granulocytic leukemia. The average number of bands per NOR in banded cells of these patients was 0.40 +/- 0.06 for the Ph NOR, not significantly different from the 0.41 +/- 0.02 per D chromosome NOR or the 0.41 +/- 0.04 per G. Across the 33 cases, the number of different Ph NOR banded in at least one cell (23 of 33, 70%) was also closely similar to the cumulative maximum number of chromosome D NOR banded per cell (137 of 198 banded, 69%) and G NOR banded (67 of 99, 67%). We conclude that the activity of rRNA genes in Ph NOR is closely similar to that of the other nine NOR in each CGL cell. In situ hybridization of 3H-labeled complementary rRNA to NOR of two patients revealed that the mean number of Ph NOR grains fell within the range of the other NOR. Also, grain distributions across the NOR of leukemic cells closely matched those of stimulated lymphocytes. Thus, a limited sampling has shown no evidence for consistent differences or changes in the rRNA gene number of Ph NOR.

Frequency of constitutional chromosome alterations in patients with hematologic neoplasias

From 1978 to 1985 cytogenetic studies were performed on 718 patients with different hematologic diseases. Nine (1.25%) had a constitutional chromosome alteration. One patient had trisomy 21, four had balanced translocations and four had sex chromosome anomalies. Although the frequency of constitutional alterations was twice that seen in the newborn population, an analysis of these data and also from the literature shows a random association between constitutional chromosome alterations and hematologic neoplasias, except for patients with Down's syndrome.

Silver-stained nucleolar organizer regions in bone marrow cells and peripheral blood lymphocytes of Philadelphia chromosome-positive chronic myelocytic leukemia patients

Silver-stained nucleolar organizer regions (Ag-NOR) in bone marrow cells and/or phytohemagglutinin-stimulated peripheral blood lymphocytes were compared between six normal healthy persons as controls and 22 Philadelphia chromosome (Ph)-positive chronic myelocytic leukemia (CML) patients, to examine if any disease associated changes occur in the expression of Ag-NOR. Although the frequency of Ag-NOR-positive cells and the number of Ag-NOR per cell were generally greater in lymphocytes than in bone marrow cells in both controls and CML patients, the Ag-stainability of these cell types in CML patients was considerably heterogeneous, compared with that found in controls. The peripheral lymphocytes of CML patients in the chronic phase, but not in the blastic phase, exhibited a significantly lowered Ag-stainability when compared with those of controls. while no such difference was observed between bone marrow cells of controls and leukemia patients in both phases of CML. In the blastic phase, however, the occurrence of Ag-NOR on the Ph of CML bone marrow cells was significantly less than expected. The present findings are discussed in relation to the existing data on the Ag-NOR expression in both normal and neoplastic cells.

Ag-NOR staining in human chromosomes: differential staining in normal and leukemic bone-marrow samples

A silver staining technique developed by Goodpasture and Bloom (1975) stains a specific protein associated with the activity of ribosomal cistrons during the preceding interphase. By counting the number of chromosomes with darkly stained nucleolus organizer regions (NORs), the number of active NORs per metaphase can be determined. A comparison of NOR activity in bone-marrow cells from leukemic patients in different stages of disease with that of bone marrow from normal, healthy individuals was conducted and differential NOR activity was detected. The control group showed significantly lower NOR activity when compared with a group of patients with acute lymphocytic leukemia (ALL). These preliminary data indicate that this simple cytochemical technique can be effectively used to differentiate between normal and ALL bone-marrow samples.

The activity of nucleolar organizer regions of human bone marrow cells studied with silver staining. I. Chronic myelocytic leukemia

The activity of nucleolar organizer regions (NORs) in chromosomes and interphase nuclei of bone marrow (BM) cells from 21 patients with chronic myelocytic leukemia (CML), including seven patients at the time of blastic crisis (BC), has been studied with silver nitrate staining. The average numbers of Ag-NOR per metaphase in PHA-stimulated peripheral blood lymphocytes from patients with CML and normal individuals were 7.1 +/- 0.3 and 7.4 +/- 0.1, respectively, indicating no statistical difference between them. Those in BM cells from patients with CML, as in the normal donors, were more heterogeneous compared to PHA-stimulated lymphocytes, and most of the metaphases (up to 67%) did not contain silver-stained NORs. The average number of Ag-positive NORs in BM mitoses from untreated patients in the chronic phases of CML and from those in the BC were similar (4.9 +/- 0.3 and 4.8 +/- 0.4, respectively). As for NORs of the Ph chromosome, they were Ag-positive in the majority of patients, including 9 of 14 in the chronic phase and 3 of 7 in the BC. This article contains some data in support of the authors' previous assumption regarding the correlation between BM Ag-NOR patterns and the degree of maturity of the cells tested in mitosis.

Heterochromatin and nucleolus organizer regions in cells of patients with malignant and premalignant lymphatic diseases

Peripheral blood lymphocytes (short-term cultures) and permanent lymphoid cell lines (long-term cultures) of patients with Hodgkin disease (5), lymphoma (1), plasma cell leukemia (1), angioimmunoblastic lymphadenopathy (1), and infectious mononucleosis (3) were investigated for C-band variants and nucleolus organizer region (NOR)-activities by C-banding and silver-staining, and compared to those of healthy adults (5) and newborn children (3). Heterochromatin polymorphisms were found in malignant diseases (33%) as well as in controls (29%). In the lymphoma patients, heterochromatin of class 3 (Patil and Lubs 1977) was seen more frequently than in the controls (83%:57%). No marker C-band variants could be detected in any of the lymphatic diseases. There was no difference in the heterochromatin polymorphism between short-term cultures (predominantly T-cells) and long-term cultures (B-cells), and there was little but inconsistant difference in the NOR-activities. Silver-staining showed differences between healthy adults (8.8 AgNORs; SD:0.5) and newborn children (6.9; SD:0.4). In the lymphoma patients we found 8.3 (SD:0.7) AgNORs. Thus, using silver staining there was no detectable increase in the number of active NORs in cells of patients with malignant diseases as an expression of increased nucleolus activation in malignancies. The remarkably low NOR-activity in infectious mononucleosis (6.7; SD:1.0) may reflect an influence of acute virus infection (Epstein-Barr virus) on NOR-activity.

Nucleolar silver-stained granules in maturing erythroid and granulocytic cells

Human and rabbit erythroid and granulocytic precursors in bone marrow have been investigated to provide information concerning the number of nucleolar silver-stained granules (SSGs), which represent active interphasic nucleolar organizer regions (NORs). The differentiation and maturation of precursor cells of both investigated cell lines are characterized by a gradual decrease in number of nucleolar SSGs. In advanced maturation stages of erythroblasts or granulocytes, which are known to lose the capacity to divide, the number of nucleolar SSGs is smaller than the reported average or maximal values of NORs determined for human or rabbit cells. Since committed stem cells from both cell lines contain several times the number of nucleolar SSGs than the last dividing maturation and differentiation stages, the number of active parts of interphasic NORs in committed stem cells seems to be increased and might represent a stock for the later stages. In addition, the number of nucleolar SSGs appear to be a very convenient marker of nucleolar biosynthetic activity in individual differentiating and maturing blood cells. The differences between erythroid and granulocytic stem cells with respect to the number of nucleolar SSGs disappear during the course of further differentiation and maturation.

Silver bands in chronic granulocytic leukemia: I. Increased banding associated with blastic transformation

We have tested the proposal that the level of silver banding in leukemic cells of Ph1 + chronic granulocytic leukemia (CGL) patients increases as the disease progresses. Blood and/or bone marrow cells from 14 patients were cultured for 24 hr before banding. In all but one case, there were two populations of mitoses, those with silver bands on their nucleolar organizing regions (NORs) and those without. The percentage of cells that banded was higher, on average, in cultures from 7 patients in blastic transformation (80%) than in 8 chronic cases (36%) or in one accelerated phase (49%). Also, the mean number of NORs stained in banded cells was higher in blastic phase (6.9) compared with chronic phase cells (4.4). Hyperdiploid cell lines were present in four cases of myeloblastic transformation. All such cells were silver banded, and the mean fraction of NORs banded in them was relatively high. An increase in silver banding with time was shown in two of the patients. It seems that silver banding does increase in CGL cells as the disease progresses. This may arise either through an increase in the rate of ribosomal RNA synthesis in leukemic cells present in the blastic phase or possibly by a decrease in the rate of degradation (or processing) of newly synthesized rRNA.

Variations in the activity of nucleolar organizers in different tissues, demonstrated by silver staining of human normal and leukemic cells

A simple silver-staining technique that demonstrates those nucleolar organizing regions of metaphase chromosomes which are transcriptionally active during the preceding interphase (AgNORs) has been applied to cells obtained from the bone marrow and mitogen-stimulated peripheral blood lymphocyte cultures of hematologically normal individuals and patients with various forms of leukemia. In the majority of bone marrow cells from the normal controls and many of the patients, the number of cells with detectable AgNORs, and the staining intensities in those cells which were Ag+, were markedly reduced compared with the levels found in blood lymphocytes. The numbers of cells having satellite associations and the numbers of chromosomes participating in these associations also generally reflected the proportions of AgNORs present. When patterns of bone marrow silver staining were compared between patients with leukemia, distinct differences were found which could be correlated with cytology. It is suggested that different cell types have characteristic AgNOR staining profiles, reflecting specific regulation of ribosomal RNA synthesis in particular cell lineages. AgNOR staining may indicate, therefore, the predominant cell types that divide in the bone marrows of patients with different forms of leukemia.

Cytogenetic studies on the nucleolar organizer region [NOR] activity in meningioma cells with normal and hypodiploid karyotypes

The association pattern and NOR silver staining of the acrocentric chromosomes was studied in normal and hypodiploid cell lines of four meningioma patients. In three cases the hypodiploid cells showed a more increased association frequency or NOR silver staining or both than the normal ones, indicating a compensatory mechanism between the NORs. Chromosomes #14 seemed to be more frequently involved in this phenomenon than other acrocentric chromosomes. From the silver staining results it was concluded that in meningioma cells, chromosomes #22 which bear active as well as inactive NORs were missing. The compensation between the NORs was probably only activated if an active NOR was lost.

Quinacrine mustard and nucleolar organizer region heteromorphisms in twins

Patterns of NOR activity in 640 metaphase spreads from twelve monozygotic (MZ) and eight dizygotic (DZ) twin pairs were studied to evaluate the heritability of this chromosomal heteromorphism. NORs were stained by a modification of the Ag-AS technique and counterstained with quinacrine mustard dihydrochloride to facilitate chromosome identification and assess their value in zygosity determination. In this study, all karyotypes were read blind with respect to zygosity and pair membership. A discriminant function analysis of pair score differences in MZ and DZ twins revealed that, in our sample, the probability of accurately determining zygosity with NOR scores was 0.93 and with QFQ scores was 0.99. We conclude that NOR and QFQ scores are highly heritable and of great value in zygosity determination. Data were collected from 687 metaphase spreads on the frequency with which an acrocentric chromosome was found in a satellite association. A significant correlation was found between this frequency and the degree of Ag-AS stain of the NOR. This study, therefore, confirms previous results showing that a high degree of NOR activity is found in those chromosomes most often involved in satellite associations.