Argyrophilic Nucleolar Organizing Regions and Ki67 Equally Reflect Proliferation in Fine Needle Aspirates of Normal, Hyperplastic, Inflamed, and Neoplastic Canine Lymph Nodes (n = 101)

Abstract

Background: The count of argyrophilic nucleolar organizing regions (AgNOR) has been considered a useful variable that reflects cellular proliferation in canine lymph nodes, but it has not been compared with other markers of proliferation.Hypothesis: Ki67 and AgNORs are equally useful as markers of tissue proliferation in fine needle aspirates of canine lymph nodes.Animals: A total of 101 dogs. Material and Methods: Prospective, observational study of a convenience sample of dogs. Two smears were prepared for a May-Gruenwald-Giemsa stain and a Ki67/AgNOR double stain. In addition, CD3/CD79a immunostaining was performed when cytologic examination revealed a lymphoma. The dogs were grouped as normal (n 5 26), reactive hyperplasia (n 5 25), lymphadenitis (n 5 31), and lymphoma (n 5 19), based on the physical examination and the cytologic findings. The AgNOR count/cell, AgNOR area/cell and the percentage of cells staining positive for Ki67 were evaluated in 100-167 cells (median, 113 cells) by using automatic image analysis.Results: Mean (SD) AgNOR counts/cell were 1.36 6 0.19 in normal dogs, 1.55 6 0.26 in lymphadenitis, 1.65 6 0.32 in reactive hyperplasia, and 3.67 6 1.08 in lymphoma. The percentage of Ki67 positive cells was 2.67 6 0.99% in normal lymph nodes, 5.04 6 3.34% in lymphadenitis, 5.36 6 2.14% in reactive hyperplasia, and 30.2 6 10.8% in lymphoma. All variables were significantly higher in dogs with lymphoma compared with the other groups (P , .0001). The sensitivity and the specificity of the AgNOR count for diagnosing lymphoma were 95 and 96% at a cutoff value of .2.04 AgNORs/cell. The cutoff value for the Ki67 positive cells was .10.40% (sensitivity, 95%; specificity, 98%).Conclusion and Clinical Importance: The results indicated that both AgNOR and Ki67 counts were good diagnostic tools for assessment of proliferation in aspirates of canine lymph nodes.

Cytodiagnostics of canine lymphomas – possibilities and limitations

“…Ki67 ICC has also proved to be an excellent method of differentiation between non-neoplastic and neoplastic proliferation of lymphatic tissue (Bauer et al 2007, Fernandes et al 2015. Moreover, Fournel--Fleury et al (1997b) have confirmed that immunocytochemistry using Ki67 antibodies is a useful method of determination of proliferative activity of lymphoma cells, and have revealed high concordance between the results of Ki67 immunocytochemistry and immunohistochemistry performed on histological samples of lymphoma tissues.…”

“…In the study of Munashinge et al (2015) the counting of Ki67 positive cells was performed in 500 cells, however, it is worth emphasizing that this analysis does not have to be so labor-consuming because counting as few as 100 cells is sufficient to obtain reliable results of Ki67 immunostaining (Bauer et al 2007). Counts can be performed in randomly chosen adjacent microscopic fields; however, unless positive cells are evenly distributed the analysis can be made in regions with the most intensive staining (Bauer et al 2007, Munashinge et al 2015.…”

“…Counts can be performed in randomly chosen adjacent microscopic fields; however, unless positive cells are evenly distributed the analysis can be made in regions with the most intensive staining (Bauer et al 2007, Munashinge et al 2015.…”

Lymphoid System

“…The most commonly (Vail et al, 1996;Vail et al, 1997;Fournel-Fleury et al, 1997b;Kiupel et al, 1998;Kiupel et al, 1999;Dank et al, 2002;Hipple et al, 2003;Whitten and Raskin, 2004;Vajdovich et al, 2004;Bauer et al, 2007). The most commonly (Vail et al, 1996;Vail et al, 1997;Fournel-Fleury et al, 1997b;Kiupel et al, 1998;Kiupel et al, 1999;Dank et al, 2002;Hipple et al, 2003;Whitten and Raskin, 2004;Vajdovich et al, 2004;Bauer et al, 2007).…”

Hemolymphatic System

“…The most commonly used proliferation markers are mitotic index, percent positive for Ki-67 antigen, percent positive for proliferation cell nuclear antigen (PCNA), and argyrophilic nucleolar organizing regions (AgNOR) quantitation (Bauer et al, 2007;Dank et al, 2002;Fournel-Fleury et al, 1997b;Hipple et al, 2003;Kiupel et al, 1998;Kiupel et al, 1999;Vail et al, 1996;Vail et al, 1997;Vajdovich et al, 2004;Whitten and Raskin, 2004). The most commonly used proliferation markers are mitotic index, percent positive for Ki-67 antigen, percent positive for proliferation cell nuclear antigen (PCNA), and argyrophilic nucleolar organizing regions (AgNOR) quantitation (Bauer et al, 2007;Dank et al, 2002;Fournel-Fleury et al, 1997b;Hipple et al, 2003;Kiupel et al, 1998;Kiupel et al, 1999;Vail et al, 1996;Vail et al, 1997;Vajdovich et al, 2004;Whitten and Raskin, 2004).…”