Argyrophilic nucleolar organizer region counts in multiple myeloma: a histopathological study on bone marrow trephine biopsies

Intranasal mast cell tumors: Clinical, immunohistochemical, and molecular features in 20 dogs

Mast cell tumors (MCTs) are an uncommon primary neoplasm of the nasal cavity in dogs for which there is a paucity of existing literature regarding their clinical behavior and molecular features. The objectives of this retrospective study were to examine the clinical findings, histopathologic and immunohistochemical features, and c-KIT mutation status of primary intranasal MCTs in dogs and identify potential prognostic factors. Canine biopsies submitted to a diagnostic laboratory in Colorado between 2010 and 2019 with intranasal neoplasms diagnosed as MCTs and no history of cutaneous or oral MCT were considered. Immunohistochemistry for CD117 and Ki67 and polymerase chain reaction (PCR) for internal tandem duplications at exons 8 and 11 of the c-KIT gene were performed. Twenty out of 1849 (1%) primary intranasal neoplasms were MCTs. Metastases were reported in 11/20 cases (55%), with the mandibular lymph node representing the most common site. One case had distant metastases to abdominal viscera. Of the cases with available outcome data, 6/14 (43%) died or were euthanized from MCT-related disease within 1 year of the onset of clinical signs. Only one case had a c-KIT mutation at exon 11. In our study, intranasal MCTs were prone to metastasize and had a generally poor prognosis, resembling the behavior of MCTs arising in other mucosal locations. While dogs with metastatic disease and survival times of <1 year tended to have atypical KIT localization, moderate to high Ki67 indices, and mitotic counts ≥8, definitive prognosticators could not be identified due to the limited number of cases with favorable clinical outcomes.

Role of Bone Marrow-Derived Stem Cells in Polyps Development in Mice with Apc(Min/+) Mutation

We explored the hypothesis that an altered microenvironment (intestinal adenomatous polyp) could modify the differentiation program of bone marrow-derived stem cells (BMSCs), involving them in colon carcinogenesis. Sublethally irradiated 8-week-old female Apc(Min/+) mice were transplanted with bone marrow (BM) cells obtained from either male age-matched Apc(Min/+) (Apc-Tx-Apc) or wild type (WT) (WT-Tx-Apc) mice. At 4 and 7 weeks after transplantation, BM-derived colonocytes were recognized by colocalization of Y-chromosome and Cdx2 protein (specific colonocyte marker). Polyp number, volume, and grade of dysplasia were not influenced by irradiation/transplantation procedures since they were similar in both untreated female Apc(Min/+) and Apc-Tx-Apc mice. At 4 and 7 weeks after transplantation, a progressive significant reduction of polyp number and volume was observed in WT-Tx-Apc mice. Moreover, the number of WT-Tx-Apc mice with a high-grade dysplastic polyps significantly decreased as compared to Apc-Tx-Apc mice. Finally, at 4 and 7 weeks after transplantation, WT-Tx-Apc mice showed a progressive significant increase of Y+/Cdx2+ cells in "normal" mucosa, whereas, in the adenomatous tissue, Y+/Cdx2+ cells remained substantially unvaried. Our findings demonstrate that WT BMSCs do not participate in polyp development but rather inhibit their growth. The substitution of genotypically altered colonocytes with Y+/Cdx2+ cells probably contributes to this process.

Disseminated tumour cells in bone marrow in experimental colon cancer: metastatic or resident?

AIM

There are conflicting data on the biological and prognostic significance of disseminated tumour cells (DTCs) in the bone marrow of colorectal cancer patients since bone metastasis is rare in this disease. The study aimed to determine the origin of bone marrow DTCs using human colorectal cancer cells in in vivo and in vitro experimental settings.

METHOD

CD1 nude female mice were xenotransplanted with SW620 cells (a colorectal cancer cell line isolated from a male patient) injected in the colon wall. At autopsy, the presence of SW620 in the bone marrow (BM), colon and other organs/tissues was recognized by detection of the epithelial marker cytokeratin-19 (CK19) and Y chromosome. In addition SW620 cells or their conditioned medium were cultured with human BM cells.

RESULTS

Macroscopically evident CK19+/Y-chromosome-positive tumours developed only in five mice receiving SW620 cells while putative DTCs (CK19+) were found in the bone marrow of all treated mice. Most of these CK19+ cells were Y chromosome negative, only few being Y chromosome positive. In vitro SW620 cells or their conditioned medium induced CK19 expression in cultured human bone marrow cells.

CONCLUSION

Experimental colorectal cancer can induce the appearance of two distinct CK19+ cell populations in the bone marrow, one of metastatic origin and the other of murine origin. These findings suggest that bone marrow cells may undergo phenotypic modifications induced by cancer cells.

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.

Modified method of AgNOR staining for tissue and interpretation in histopathology

This study was conducted in the department of Pathology King Edward Medical University, from June to December 2002 to introduce the new method of AgNOR staining and its interpretation to increase its reliability. A total of 60 brain specimens were stained with modified AgNOR technique. The diagnosis of malignancy was made on H & E staining. AgNOR counts, variation in size and dispersion of AgNOR dots in cells were graded and compared in malignant and non-malignant lesions. Modified method of AgNOR staining and interpretation was an easy, reliable and reproducible alternative to traditional AgNOR techniques for evaluating proliferation activity of cells in malignant and benign brain lesions. mAgNOR counts of different grades of astrocytoma (2.97+/-0.96, 3.97+/-0.43, 6.01+/-2.74 and 8.01+/-3.56) were significantly (P<0.01) greater when compared with counts of normal brain (0.40+/-0.01), and reactive gliosis (0.60+/-0.01). AgNOR size and dispersion were of higher grade in a significantly greater proportion of malignancy when compared with benign conditions (P<0.05). The AgNOR dots were brighter and more clear with modified staining when compared with previous studies. We conclude that modified AgNOR staining technique is simple, quick and reliable to evaluate cell proliferation by detecting AgNORs size and dispersion. In future, AgNOR size and dispersion should be considered rather than the count only. We recommend the use of morphometry for AgNOR size in future. We also recommend the use of modified AgNOR staining for obtaining sound and confidant results in routine paraffin sections.

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.

Staining of the nucleolar organizer regions: relevance in hematology

There is growing interest in staining for the nucleolar organizer regions to detect nucleolar organizer region-associated proteins. In some cases, this technique facilitates the study of hematological disorders and allows us to distinguish between certain pathologies. Furthermore, it can provide information about cell proliferation, activity and malignancy. This paper attempts to give the recent advances in the use of the staining of nucleolar organizer regions and its clinical relevance in hematology.

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.

AgNORs and myeloma prognosis

The argyrophilic nucleolar organizer regions (AgNORs) were analysed in bone marrow biopsies from 80 patients with multiple myeloma (MM) at presentation. The mean AgNOR number per MM cell (AgNOR counts) and their distribution within the nucleus (configuration) were assessed. AgNOR counts were significantly associated with several recognized prognostic factors: Durie and Salmon clinical staging system (p = 0.02), percentage of plasma cells (PCs) in aspirates (p = 0.01) and in bone marrow biopsies (p = 0.0000), pattern of bone marrow involvement (p = 0.0003), calcaemia (p = 0.0005) and creatininaemia (p = 0.0003). AgNOR counts were also associated with the degree of PC differentiation (p = 0.0000). A single central cluster of 2-3 large-sized AgNORs (configuration A) was evident in most G1 MM; one cluster of 4-5 medium-sized dots or two clusters of 2-4 dots (configuration B) were seen in most G2 MM; many small-sized, scattered dots were present in G3 MM (configuration C). AgNOR counts and configuration were related to the prognosis: in the univariate analysis, the 5 year survival rate was 7% for cases with > 4.5 AgNORs/cell and 46% for cases with < or = 4.5 AgNORs/cell (p = 0.01), 53% for configuration A, 12% for configuration B and 0% for configuration C (p = 0.0000). AgNOR counts (p = 0.02) and configuration (p = 0.000) were independent prognostic variables in the multivariate analysis. The AgNOR counts were significantly higher in "fulminant myeloma" than in less aggressive cases (p = 0.002). The plasma cell labelling index (LI%), evaluated in 44 MM patients, showed significant correlation with prognosis: the 5 year survival rate was 51% for LI% < or = 1 and 17% for LI% > 1 (p = 0.02). More than 70% of patients with low LI% had low AgNOR counts and more than 70% of patients with high LI% had high AgNOR counts (p = 0.007). AgNOR counts and configuration reflect the myeloma cell mass, the degree of differentiation and the kinetics of the myeloma cells. They offer an exact evaluation of the tumour characteristics and can be useful additional parameters for MM prognosis.

Argyrophilic nucleolar organizer region counts and prognosis in multiple myeloma

The prognostic significance of argyrophilic nucleolar organizer regions (AgNORs) has been evaluated in bone marrow trephine biopsies from 64 patients with multiple myeloma (MM) prior to therapy. The univariate Kaplan-Meyer survival analysis showed a significant correlation between survivals and AgNOR counts (median of survival 51.3 months for cases with < or = 4.62 AgNORs per plasma cell (PC) versus 16 months for cases with > 4.62 AgNORs per PC; P = 0.0000) or AgNOR distribution in PC nucleus (AgNOR configuration) (median of survival 71.67 months for cases with tightly grouped AgNORs, 16.26 for partially grouped and 11.74 for dispersed AgNORs; P = 0.001). Significant prognostic correlations were also found for monoclonal immunoglobulin type (P = 0.008), platelet counts (P = 0.0078), serum creatinine level (P = 0.0001), Durie's clinical stage (P = 0.02), percentage of plasma cells in bone marrow biopsies (BMPC%) (P = 0.005), pattern of medullary involvement (P = 0.003) and PC atypia (P = 0.009). Borderline result was detected for the percentage of PCs in aspirates (P = 0.06). No significant correlation was found between prognosis and patients age, sex, haemoglobin level, serum albumin or calcium level, marrow cellularity and excess of haemosiderin. Multivariate survival analysis showed that only two variables were significantly correlated with prognosis: AgNOR counts (P = 0.003) and AgNOR configuration (P < 0.001). In addition, the analysis of variance showed significant association between AgNOR number and platelet counts, haemoglobin level, calcaemia, creatininaemia, clinical stage, percentage of PCs in aspirates, BMPC%, pattern of medullary involvement, PC atypia, marrow cellularity and configuration of AgNORs. Our results indicate that AgNOR counts and configuration have prognostic and diagnostic value and therefore they are useful independent parameters to assess the pretherapeutic aggressiveness of multiple myeloma.