Video image analysis of AgNOR distribution in the normal and adenomatous colorectum

Evaluation of the efficacy of AgNOR as a proliferative marker in oral leukoplakia: A morphometric analysis

Background:

Silver stainable nucleolar organizer regions (AgNORs) are replicatory markers which may have a place in objectively characterizing dysplasia.

Materials and Methods:

A study of various morphometric parameters related to AgNORs was performed in basal and parabasal layers of normal human oral epithelium, nondysplastic leukoplakia, and dysplastic leukoplakia employing photomicrographs of silver stained paraffin embedded sections using image analysis, to assess the usefulness of these parameters in distinguishing dysplastic leukoplakia from nondysplastic oral leukoplakia.

Results:

Out of various mean AgNOR related parameters, AgNOR count, area, perimeter, and proportion were found to be higher in dysplastic leukoplakia as compared to nondysplastic leukoplakia. On statistical analysis, AgNOR count showed statistically significant differentiation between dysplastic and nondysplastic leukoplakia. While other parameters can distinguish normal oral epithelium from dysplastic and nondysplastic leukoplakia.

Conclusion:

To conclude, the AgNOR count is the most appropriate marker to differentiate between dysplastic and nondysplastic leukoplakia.

Value of Silver Binding Nucleolar Organiser Regions (AgNOR) in Squamous Cell Carcinomas of Upper Aero-digestive Tract

BACKGROUND

Study of Silver-binding nucleolar organizing regions (AgNORs) in 50 cases of squamous cell carcinomas (SCC) of upper Aero-digestive tract was carried out with an aim of correlating AgNOR positivity with histological grade of tumour and evaluating value of AgNOR staining in predicting the progress of disease.

METHODS

Tissue sections of the cases were stained with 50 percent silver nitrate solution for AgNOR evaluation and the data analysed. All the sections were also stained with haematoxylin and eosin stain for tumour typing and grading.

RESULTS

In this study, the mean AgNOR (mAgNOR) score of normal squamous epithelium (50 cases) was 1.56 (range1.00-2.80), that of well differentiated squamous carcinoma (27 cases) was 3.29 (range 2.4-4.6), moderately differentiated squamous carcinoma (21 cases) was 4.29 (range 2.7-5.6) and of poorly differentiated squamous cell carcinoma (2 cases) was 5.21. The mAgNOR scores were statistically significant. Comparison of the percentage AgNOR (pAgNOR) scores between well differentiated and moderately differentiated carcinomas showed that all the pAgNOR values (1-9) were significant. However, pAgNOR 3 and pAgNOR 4 were most significant. Cut off values for pAgNOR score to differentiate between the various grades of squamous cell carcinomas could not be calculated due to lack of data on survival rates.

CONCLUSION

AgNOR technique can definitely be used as a supportive tool to routinely performed Hemotoxylin and Eosin staining and may help in prognosis as well as therapeutic decision-making in squamous cell carcinomas. Studies of larger number of cases in a prospective study are needed to arrive at more substantial conclusions.

Argyrophilic staining of nucleolar organizer region count and morphometry in benign and malignant melanocytic lesions

Differentiation between malignant melanomas (MMs) and benign nevi based on histologic features can sometimes be difficult. This study evaluated the diagnostic effectiveness of argyrophilic staining of nucleolar organizer regions (AgNORs) in separating benign nevi from MMs by assessing 27 compound nevi (CN), 20 dysplastic nevi (DN), 10 Spitz nevi (SN), and 24 MMs. Both AgNOR count and morphology variables were measured from the superficial, middle, and deep zones of the lesions using video image analysis. Malignant melanomas had a significantly greater AgNOR number per nucleus, mean AgNOR area per nucleus, and variation in AgNOR area per nucleus compared with all types of benign nevi (p < 0.05). In multivariate discriminant analysis using a combination of four AgNOR counts and morphometric parameters, all CN and DN, 8 of 10 SN, and 23 of 24 MMs could be correctly classified as benign or malignant. The results suggest that both AgNOR count and morphology help to separate benign and malignant melanocytic lesions and that the combination of both sets of parameters improves their discriminating ability.

The AgNoR count in ulcerative colitis with and without dysplasia

The numbers of specific intranuclear AgNOR silver precipitates (AgNORs) and their relation to the Inflammatory Bowel Disease-Dysplasia Morphology Study Group's classification were studied in 134 colonscopic biopsy specimens of ulcerative colitis (UC) with and without dysplastic findings from 73 patients with active and inactive disease. In addition, 40 cases of colonic adenocarcinomas and 22 normal colonic mucosae were also assessed for comparison with the one-step silver staining AgNOR technique. Statistical comparison of the mean AgNOR number revealed a highly significant inter-class difference (P < 0.001) between UC without dysplasia and UC with dysplasia as well as between active and inactive UC. On the contrary, the AgNORs count did not separate colonic adenocarcinomas from UC with dysplasia either high or low grade nor these three classes from the group of UC with indefinite dysplasia. The quantitative evaluation of epithelial changes occurring in UC by the AgNOR method may help to establish the clinical management of colitis patients, in addition to qualitative morphological criteria.

Gallbladder carcinoma: a video image analysis of AgNOR distribution and its relation to tumour stage and grade

The amount and distribution of interphase argyrophilic nucleolar organizer regions (AgNORs) was studied in 51 gallbladder surgical specimens including 32 primary carcinomas, 10 adenomas and 9 cases of chronic cholecystitis with calculi. The mean nuclear AgNOR area (NORA) and the AgNOR distribution score (NORDS), i.e. the percentage of cells carrying nucleolar aggregates with more than 6 distinct silver dots, were evaluated in 200 epithelial nuclei per specimen by means of automated image analysis and direct counting respectively. Statistical analysis (variance analysis and Student-Neuman-Keuls' test) performed on the pooled mean AgNOR values showed a significant difference (p < 0.001) between carcinomas and non-carcinomatous lesions. Both NORA and NORDS highly discriminated carcinomas with histopathological grade 4 versus cases with grade 1, 2 or 3 (p < 0.001); a less statistically significative p value (< 0.05) was encountered when NORDS values of well differentiated grade 1 carcinomas and adenomas were compared. The NORA parameter permitted the discrimination of stage IV versus stage I carcinomas (p < 0.001), while carcinomas in stage IV and those in stage II were distinguished with a p < 0.05; the NORDS parameter allowed also to distinguish stage IV from both stage I or II tumours (p < 0.001). Our results indicate that the above-mentioned AgNOR parameters may be utilized as additional, more objective quantitative criteria in the clinical-pathological assessment of the outcome of gallbladder carcinomas.

Nuclear DNA content and nucleolar organizer regions in colorectal cancer

The prognostic value of nuclear DNA content and argyrophilic nucleolar organizer regions (AgNOR) is still controversial in colorectal cancer. Sixty patients with colorectal cancer were studied by flow cytometric DNA analysis and AgNOR measurement, and their prognostic significance was tested. DNA index was closely linked to depth of invasion and lymph node metastasis, while AgNOR count did not correlate with such parameters. The survival curve was strongly influenced by depth of invasion, lymph node metastasis, and Dukes' stage but was not affected by DNA ploidy and AgNOR count. These results indicate that neither DNA ploidy nor AgNOR count correlates with survival of patients, although DNA ploidy is linked to progression of colorectal cancer.

Role of the pathologist in biomarker studies

Cancer chemoprevention is defined as intervention by chemical agents prior to invasion to inhibit or slow the carcinogenic process. Using surrogate endpoint biomarkers in chemoprevention studies may reduce the size, length and cost of clinical prospective randomized trials in high-risk populations. Intermediate biomarkers are measurable alterations in the tissues at risk and include differentiation, genetic composition, biochemical expression, and proliferation. Assessment is possible because invasive epithelial neoplasms are known to begin as intraepithelial proliferations with a spectrum of cellular abnormalities extending to carcinoma in situ. Genetic heterogeneity begins in the intraepithelial phase; a stochastic accumulation of genetic errors characterizes the progression of clonal evolution within the tumor through the process of invasion and metastasis. Pathologic features associated with this process include tumor classification as well as whether it is intraepithelial or invasive. If the process is intraepithelial, the grade and extent of the intraepithelial lesion are reported. If the neoplasm is invasive, tumor size, extent, degree of differentiation (histologic and nuclear grade), mitotic rate, vascular invasion, and lymph node involvement are evaluated. In assessing biomarkers relevant chemoprevention, and without complete regression of the neoplasm with the chemopreventive agent or agents, measurable parameters along with histopathologic features are applicable. Three methods readily applicable for this purpose that can be applied to paraffin-embedded, formalin-fixed tissue include quantitative pathology, immunohistochemistry, and molecular biologic applications. These methods require some consistency in handling and processing the tissues under study; results may deteriorate due to a number of processing variables, including time to fixation, time in fixative, and fixative type. Quantitative pathology, including static image analysis and flow cytometry, can determine total DNA content. Using static image analysis, very small tumors can be studied. In addition, adjacent intraepithelial and invasive components of a tumor may be studied from a single slide. Steroid receptors, oncogenes, and other proteins detectable through immunohistochemical or molecular biologic methods can be quantitated by this technique as well. Cell cycle synthetic function is assayable by both methods. Flow cytometry can calculate the total percentage of cells in S-phase, or the tumor cell S-phase fraction based on the percentage of cells detected between the G0, G1 peak and the G2 + M peak. A similar approach is generally not applicable with current image analysis equipment; however, cell cycle related proteins such as MIB-1 (Ki-67 associated) can be quantified. Immunohistochemical methods can employ a wide variety of monoclonal antibodies to detect oncogene related proteins, including HER-2/neu (c-erbB-2) and p53. Molecular biologic methods, including in situ hybridization, polymerase chain reaction, and in situ PCR, can have many applications when applied to paraffin-embedded tissues, including detection of viral DNA, identification and measurement of apoptosis, and defining gene deletions.

Image cytometry: current applications and future trends

Image cytometry has numerous clinical and research applications and is particularly useful in anatomic pathology for the study of malignant lesions. Modern image systems encompass morphometry, densitometry, neural networks, and expert systems. Rapid advances in technology and the development of user-friendly systems have provided pathologists with an alternative to flow cytometry, particularly useful in the evaluation of small or hypocellular specimens. The most common current application of image cytometry is for DNA analysis, followed by quantitation of immunohistochemical staining. Newer uses under active investigation include development of expert systems that may act as diagnostic consultants in the future. Beyond DNA analysis, image cytometry holds great promise for improved tumor classification, for screening and surveillance in high-risk populations, and as a tool to improve diagnostic ability. This article discusses types of image analysis systems, specimen preparation, data acquisition, current applications in specific organ sites, and possible future applications.