Nucleolar organizer regions (NORs) staining and proliferating cell nuclear antigen (PCNA) immunostaining in mucosa-associated lymphoid tissue (MALT) gastric lymphomas

AgNORs count and DNA ploidy in liver biopsies from patients with schistosomal liver cirrhosis and hepatocellular carcinoma

OBJECTIVES

Argyrophilic nucleolar organizer regions (AgNOR) proteins are a set of argyrophilic nucleolar proteins that accumulate in highly proliferating cells, whereas their expression is very low in nonproliferating cells. The present study aimed to investigate the potential of DNA flow cytometry (FCM) and AgNORs count in the assessment of cellular kinetics of liver cirrhosis and hepatocellular carcinoma.

DESIGN AND METHODS

Small-needle liver biopsies (217) were included and were taken from 84 patients with hepatocellular carcinoma (HCC) (one biopsy from tumor lesion and the other from residual nontumor) liver tissues. Only one biopsy was taken from 49 patients with liver cirrhosis. One part of biopsy was subjected to flow cytometry, and the other, to histopathology and AgNORs counting.

RESULTS

An aneuploidy was shown in 44.5% of liver cirrhosis and in 78.6% of tumor sites. Aneuploid HCC cases showed high AgNORs count compared with diploid cases (3.407+/-1.18 vs. 1.74+/-0.9). An extremely significant increase in AgNORs count in tumor lesion (P<0.001) was found compared with residual liver tissues, liver cirrhosis and normal liver (3.89+/-0.827, 1.49+/-0.52, 1.62+/-0.29, and 1.3+/-0.17, respectively). In liver cirrhosis, dysplasia showed a significant relationship with ploidy (P<0.001) and AgNORs count (P<0.05).

CONCLUSION

AgNORs count and DNA ploidy analysis of core biopsy specimens are useful in the assessment of cellular kinetics of liver cirrhosis and hepatocellular carcinoma.

Application of rapid CD3 immunophenotype analysis and argyrophilic nucleolar organizer region (AgNOR) frequency to fine needle aspirate specimens from dogs with lymphoma

Determinations of CD3 immunoreactivity (CD3-IR) and argyrophilic nucleolar organizer region (AGNOR) frequency from fine needle aspirate (FNA) samples were compared with those from formalin-fixed, paraffin-embedded surgical biopsy samples in 51 dogs with lymphoma. Both CD3-IR (using a rapid EPOS polymer system) and AGNOR techniques were readily applied to FNA samples. CD3-IR from FNA samples matched those of histologic samples with 100% concordance. A linear relationship (r=0.981; P<0.001) was found between AGNOR frequency obtained from FNA samples and those obtained from surgical biopsy samples. Application of the techniques presented here should allow clinically relevant information to be procured rapidly and inexpensively. As CD3-IR and AGNOR frequency have been shown to be predictive of response to combination chemotherapy in dogs with lymphoma, such information could be used to better educate clients as to the likelihood of achieving meaningful responses, as well as allowing prospective tailoring of individual treatments in future trials prior to initiating therapy.

Changes in pattern of immunoglobulin heavy chain gene rearrangement and MIB-1 staining before and after eradication of Helicobacter pylori in gastric mucosa-associated lymphoid tissue (MALT) lymphoma

Gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphomas are strongly associated with infection by Helicobacter pylori (H. pylori). Antibiotic treatment for H. pylori induces a sustained remission in a significant number of patients. We report here the outcome in 13 patients with gastric low-grade MALT lymphomas or suspected gastric lesions, treated for eradication of H. pylori. Patients were followed closely with sequential histological studies, polymerase chain reaction (PCR) amplification of the immunoglobulin heavy chain (IgH) gene and immunohistochemistry for MIB-1. Antibiotic therapy resulted in eradication of H. pylori in all but one case, as assessed histologically. In 12 cases with successful eradication, complete regression was observed histologically in 9 cases (75%) and no regression in 3 (25%). In 7 of 9 (78%) patients who had a complete remission, clonal bands of IgH gene detected on PCR before therapy disappeared after therapy. All 9 patients with complete regression showed a reduced number of MIB-1 positive cells, while 4 cases with no change or disease progression showed no change or increased number of MIB-1 positive cells. There was a strong relationship between density of MIB-1-positive cells and histological score. These results indicate that combination analysis of PCR of IgH and MIB-1 seems to represent a very good current approach for the diagnosis of gastric low-grade MALT lymphoma and to assess the effects of chemotherapy, especially in problematic cases.

Spontaneously occurring tumors of companion animals as models for human cancer

Spontaneous tumors in companion animals (dog and cat) offer a unique opportunity as models for human cancer biology and translational cancer therapeutics. The relatively high incidence of some cancers, similar biologic behavior, large body size, comparable responses to cytotoxic agents, and shorter overall lifespan are the factors that contribute to the advantages of the companion animal model. The tumor types that offer the best comparative interest include lymphoma/leukemia, osteosarcoma, STS, melanoma, and mammary tumors. With the increase in new therapeutic agents (traditional chemotherapy, gene therapy, biologic agents, etc.), the companion animal model can provide useful populations to test new agents where efficacy and toxicity can be examined.

Proliferative Activity of Epidermal Basal Cells after Wounding

Quantitative changes in nucleolus organizer regions (NORs) are known markers of proliferation that can be demonstrated by a specific silver staining technique on paraffin-embedded sections. Wounding of skin induces proliferation of basal epidermal cells at the wound margin. The degree of proliferation depends on the survival time and can be measured by morphometric assessment of argyrophilic NORs (AgNORs). Following incision wounding of the pinnae, rats were allowed to survive for different intervals (7 rats per interval) up to 120 hours. Before each sacrifice, biopsies were taken and incubated in a bromodeoxyuridine (BrdU) solution, embedded in paraffin, and stained with an antibody against BrdU. At the same time morphometric analysis of AgNOR counts was performed on sections made from the same material. BrdU incorporating nuclei were assessed by simple counting, whereas morphometric analysis of AgNOR counts was computer aided. Both methods revealed an increase in the number of proliferating cells, a plateau phase being reached after about 36 hours, followed by a decline after about 70 hours. Both methods thus allowed a reliable temporal classification of the skin injury according to survival time. The molecular background of the AgNOR changes in relation to the proliferation of cellular elements is discussed in detail.

PCNA/AgNOR and Ki-67/AgNOR double staining in oral squamous cell carcinoma

This study was performed on oral squamous cell carcinomas (OSCC) in order to investigate the relation between the number of interphase silver-stained nucleolar organizer regions (AgNORs) and the immunolabeling of proliferation-associated markers, using antibodies to Ki-67 and proliferating cell nuclear antigen (PCNA). Fifteen consecutive cases of oral squamous cell carcinoma were used and a double staining technique was performed in order to quantify the number of NORs in PCNA-positive and -negative cells as well as in Ki-67-positive and -negative cells. Our results showed a higher mean number of AgNORs in PCNA- and Ki-67-positive cells than in PCNA- and Ki-67-negative cells. We concluded that there is an association between cell proliferation and AgNOR score in OSCC.

Feline lymphoma (145 cases): proliferation indices, cluster of differentiation 3 immunoreactivity, and their association with prognosis in 90 cats

Paraffin-embedded, formalin-fixed tissue samples from 145 cats with lymphoma were analyzed for cluster of differentiation 3 (CD3, a surface antigen) immunoreactivity, argyrophilic nucleolar organizer region (AgNOR) frequency, and proliferating cell nuclear antigen labeling index (PCNA-LI). This information along with signalment, anatomic site, and feline leukemia virus (FeLV) antigen status was used to determine the potential of these indicators to predict response to therapy, remission, and survival times, and to characterize cats with lymphoma in the era of general availability of FeLV testing and vaccination. Alimentary lymphoma, primarily occurring in older, FeLV-negative cats, was the most common site of involvement. Although the majority of tumors from FeLV-positive cats were CD3-immunoreactive, only one half of CD3-immunoreactive tumors occurred in FeLV-positive cats. Median remission duration and survival times were 126 days and 143 days, respectively, for all cats. Measures of tumor cell proliferation (AgNOR frequency and PCNA-LI) and CD3-immunoreactivity were not predictive of outcome. When all prognostic factors were accounted for by multivariate analysis, response to therapy, FeLV status, and clinical substage were predictive of outcome. FeLV-negative cats that achieved a complete response following induction therapy were likely to have durable (i.e., > 6-month) responses, particularly when doxorubicin was included in the chemotherapy protocol. However, FeLV-positive cats had significantly shorter remission and survival times with available chemotherapeutic protocols.

Mycosis fungoides: expression of C-myc p62 p53, bcl-2 and PCNA proteins and absence of association with Epstein-Barr virus

The expression of C-myc p62, bcl-2, p53, PCNA and EBV-encoded LMP-1 proteins was studied by immunohistochemistry on paraffin-embedded skin specimens from 14 patients with early stage (premycotic erythema and second stage plaques) mycosis fungoides (MF), 21 patients with advanced stage MF (third stage plaques and tumors), 3 patients with Sezary's syndrome (SS) and 3 patients with pleomorphic medium and large cell cutaneous T-cell lymphomas (PML-CTCL). All 41 cases were also screened for the presence of EBV by using RNA in situ hybridization with EBER 1/2 oligonucleotides. Increased expression of C-myc p62, p53 and PCNA proteins was found in PML-CTCL and advanced stages of MF as compared to early stages of MF. These results suggest a relationship between levels of C-myc p62, p53 and PCNA proteins and aggressiveness of the cutaneous T-cell lymphomas. Furthermore, C-myc p62 and bcl-2 proteins were found to be frequently coexpressed in the present series. In view of the background information from in vitro findings and animal models that cooperation of C-myc and bcl-2 is important for lymphomagenesis, our results suggest that coexpression of these oncogenes may be implicated in the pathogenesis and/or the progression of cutaneous T-cell lymphomas. Neither LMP-1 expression nor EBV EBER l/2 transcripts were detected in our series suggesting that EBV is not involved in the pathogenesis of cutaneous T-cell lymphomas.