Identification of nucleolar organizer regions in non-neoplastic and neoplastic hepatocytes by the silver-staining technique

A statistical model predicting high hepatocyte proliferation index and the risk of developing hepatocellular carcinoma in patients with hepatitis C virus-related cirrhosis

BACKGROUND

Incidence of hepatocellular carcinoma in hepatitis C virus-related cirrhosis is 4% per year. Although cost-effective, current screening could be improved.

AIM

To develop a statistical model including non-invasive parameters able to identify patients at high risk of developing hepatocellular carcinoma.

METHODS

One hundred and fifty-eight patients (73F:85M) with compensated chronic hepatitis C virus liver disease underwent evaluation, including argyrophilic nucleolar organizer regions proliferation index, and were followed up for 56.18 +/- 1.44 months.

RESULTS

Fifty-six patients had chronic hepatitis without cirrhosis and low argyrophilic nucleolar organizer regions proliferation index (< or =25%), 65 had hepatitis C virus-related cirrhosis and low argyrophilic nucleolar organizer regions proliferation index and 37 had hepatitis C virus-related cirrhosis and high argyrophilic nucleolar organizer regions proliferation index (>25%). Groups were similar for gender and viral genotype distribution. None of the patients with chronic hepatitis without cirrhosis developed hepatocellular carcinoma, compared with 6.1% of low argyrophilic nucleolar organizer regions proliferation index and 30.6% of high argyrophilic nucleolar organizer regions proliferation index (P = 0.002). By multivariable logistic regression analysis, the following parameters were independently associated with hepatocellular carcinoma development and used for the development of the statistical model: platelets (OR 0.98), gamma-globulins (OR 0.111), alanine aminotransferase/aspartate aminotransferase ratio (OR 0.07), serum ferritin (OR 1.0) and ultrasonographic pattern (coarse OR 2.9, coarse nodular OR 10.12). The statistical model properly allocated 95.9% of patients with low argyrophilic nucleolar organizer regions proliferation index and 72.2% of patients with high argyrophilic nucleolar organizer regions proliferation index.

CONCLUSIONS

The model, to be validated in large prospective studies, may help tailoring screening according to the risk of hepatocellular carcinoma development.

Nucleolar hypertrophy correlates with hepatocellular carcinoma development in cirrhosis due to HBV infection

Patients with cirrhosis are at significant risk for hepatocellular carcinoma (HCC). The aim of the present study was to evaluate the relationship between the percentage of hepatocytes showing nucleolar hypertrophy and the development of HCC in cirrhosis of different causes. A total of 111 cirrhotic patients were studied, with a mean follow-up period of 83.3 months. Histologic sections from liver biopsy specimens were silver stained for selective visualization of the nucleolus; the nucleolar area was measured by image cytometry. Nucleoli with a size of 7 microm(2) or greater were considered to be hypertrophic. The nucleolar index was obtained by calculating the percentage of hepatocytes disclosing a nucleolar area of 7 microm(2) or greater. During the observation time, HCC was diagnosed in 39 of 111 patients. The incidence rate of HCC was greater in patients with nucleolar indexes of 2.5 or greater than in patients with nucleolar indexes of less than 2.5 (16.49%/y vs. 3.41%/y, respectively; P <.0001). The capacity of the nucleolar index to predict HCC development was separately tested in groups of patients divided by etiology, and it was found to be particularly relevant in hepatitis B virus (HBV)-related cirrhosis (P =.0006). Among patients with hepatitis C virus (HCV) infection, high nucleolar-index values were associated with a greater risk for HCC development, but the difference in the incidence rate of HCC between groups with a nucleolar index of 2.5 or greater and less than 2.5 was not statistically significant (P =.0944). In conclusion, our results have shown that high percentages of hepatocytes showing nucleolar hypertrophy significantly predict HCC development in patients with HBV infection, whereas their predictive value in HCV-related cirrhosis seems to be lower.

Studies on the proliferative activity of diethylnitrosamine-induced hepatocellular carcinomas in monkeys

In this study, synthetic phase fractions (SPFs) determined by flow cytometry and AgNOR counts were analysed in benign liver lesions (regenerative nodules and adenomas), hepatocellular carcinomas (HCCs), and lung metastases of a monkey hepatocarcinogenesis model to find out if AgNOR counts and SPFs can discriminate between malignant and non-malignant liver lesions. The average per cent SPF values and the AgNOR counts were significantly (P = 0.001) increased in regenerative liver nodules (5.30 per cent; 4.96), adenomas (5.34 per cent; 3.46) and well-differentiated HCCs (6.75 per cent; 4.47), compared with the untreated control livers (3.18 per cent; 0.98), but the differences between these three groups were not significant. In the poorly differentiated HCC group, however, the average SPF value (9.60 per cent) and AgNOR count (7.14) were significantly higher than in any of the other liver lesions examined. A significant correlation was found between the SPF values and AgNOR counts on the one hand, and differentiation and cytological grade of the HCC samples on the other. The results of this study show that the SPF values and AgNOR counts are not reliable in differentiating between regenerating liver nodules, adenomas, and experimental well-differentiated HCCs. The SPF value, however, may serve as a prognostic factor in HCC, since it was found to be significantly higher in HCCs with lung metastasis than in those without.

The potential for the use of cell proliferation and oncogene expression as intermediate markers during liver carcinogenesis

Intense research using animal models has indicated that chemically-induced rat liver cancer proceeds through multiple, distinct stages that can be characterised morphologically and biochemically. Primary human liver cancer, with hepatitis B and other environmental factors such as poor nutrition and food contaminating mycotoxins as contributing etiological factors, is one of the major causes of cancer deaths in African, Asian and some Western countries. Recent advances in surgical and diagnostic techniques have also allowed the identification of potential morphological precursors of primary human liver cancer, and suggested a model consistent with the concepts of initiation--promotion--progression as in the rat. The expression of proliferating cell nuclear antigen (PCNA), silver-staining nucleolar organiser regions (AgNOR), oncogenes and the tumor suppressor gene p53 in preneoplastic and neoplastic lesions of rat and human livers is presently reviewed. This undertaking is an attempt to evaluate whether the current knowledge regarding molecular mechanisms of carcinogenesis is sufficient to permit the use of these molecular parameters as 'intermediate' markers in studies of risk assessment and cancer prevention, without having to resort to tumor appearance as an end-point.

The nucleolar organizer regions in hyperplastic and tumorous lesions of the human liver

The alterations of the argyrophil nucleolar organizer regions (AgNORs) have been studied in hyperplastic and neoplastic human liver lesions. The material studied included: 11 focal nodular hyperplasias (FNH), 3 adenomas, 19 hepatocellular carcinomas (HCC), 2 hepatoblastomas, 8 liver metastases. In 5 cases tumor-free (normal) liver was also available for study. The mean AgNOR numbers were significantly increased in all of these lesions (in FNHs 3.36 +/- 1.43, in the adenomas 2.48 +/- 1.29, in the HCCs 3.32 +/- 1.43, in the hepatoblastomas 3.33 +/- 1.33 and in the metastases 4.86 +/- 1.54) compared to those observed in normal liver (0.86 +/- 0.85). The highly increased AgNOR number in FNHs was particularly surprising and it seemed to us that based on AgNOR numbers the FNHs could be divided into two groups. With the exception of hepatoblastomas in all primary liver lesions the AgNOR counts distributed on a rather broad scale resulting in overlapping in hyperplastic and tumourous cases. The authors concluded that the AgNOR counts reflect only the proliferative activity of a given cell population and at least in the liver they cannot serve as basis for distinction between the hyperplastic, benign and malignant neoplastic lesions.

A correlation of argyrophilic nucleolar organizer regions with stages of hepatocellular carcinoma

BACKGROUND

Recently, the number and morphologic features of argyrophilic nucleolar organizer regions (AgNOR), silver-stained nucleolar organizer regions, were thought to reflect the cellular proliferative activity and the grade of malignancy. In liver diseases, it has been reported that AgNOR scores for hepatocellular carcinomas (HCC) were significantly higher than those for benign and borderline lesions; the scores increased with histologic tumor grade.

METHODS

Using the colloid silver staining technique to reveal AgNOR, 64 liver biopsy specimens with HCC were examined of which 14 had Stage I disease, 20 had Stage II, 14 had Stage III, 10 had Stage IVA, and 6 had Stage IVB (by International Union Against Cancer criteria).

RESULTS

AgNOR in nuclei were divided into two types. Type 1 (T1-NOR) contained large and medium-sized brown dots with well-defined margins. Nucleoli were included in this type. Type 2 (T2-NOR) had fine black single dots and clusters without well-defined margins outside T1-NOR, but within the nucleus. The size and irregularity of T1-NOR changed with the progress of cancerous stages. The increase in the number of T2-NOR contributed preponderantly to the overall increase in Ag-NOR scores.

CONCLUSIONS

These results suggest that HCC with smaller and/or irregular T1-NOR in combination with high T2-NOR scores have a more aggressive potential. AgNOR may be useful indicators for evaluating the progress of HCC.

Demonstration of nucleolar organizer regions in lung carcinoma by silver staining

Nucleolar organizer regions (NORs) were investigated in lung carcinomas by silver staining. This method was applied to 111 lung carcinoma specimens, including 40 with squamous cell carcinoma (SCC), 42 with adenocarcinoma (ADENO), 8 with adenosquamous carcinoma (ADESQ), 8 with small cell carcinoma (SMCC), 6 with large cell carcinoma (LGCC), and 7 with typical carcinoid tumors (CAOID). The mean AgNOR counts of ADENO, SCC, ADESQ, SMCC, and LGCC were significantly higher than those of the normal bronchial surface and those of the glandular or alveolar epithelium. The mean AgNOR count of CAOID was significantly higher than those of the normal glandular and alveolar epithelium but not that of the surface epithelium. The mean AgNOR count of SCC was significantly higher than that of bronchial squamous metaplasia, and the count of SMCC was significantly higher than that of CAOID. Within the same cancer category, the mean number of AgNORs increased in parallel with the histological tumor grades. These results indicate that the AgNOR method is useful for differentiating lung carcinoma from its normal counterparts and for evaluating histological tumor grades in the same lineage of lung carcinoma.

Demonstration of nucleolar organizer regions in intrahepatic bile duct carcinoma by the silver-staining technique

A silver colloid technique to identify argyrophilic nucleolar organizer region associated protein (AgNOR) was applied to 43 cases of intrahepatic bile duct carcinoma (cholangiocarcinoma, CC), 2 with bile duct adenoma (BDA), 5 with focal duct epithelial hyperplasia (FEH) associated with hepatolithiasis, 15 with posthepatitic ductular proliferation (PHDP) associated with massive or submassive hepatic necrosis and 20 of normal liver. In the present study, only discrete, easily counted black dots within nuclei and silver-stained nucleolus were counted under a magnification of x 400 without oil-immersion objectives. The mean AgNOR count of CC was significantly higher than those of BDA, FEH, PHDP and normal controls (P less than 0.05, P less than 0.001, P less than 0.01, and P less than 0.001, respectively). Among CCs the mean AgNOR numbers of papillary adenocarcinoma (pap), moderately (tub2) and poorly differentiated (por) adenocarcinoma, and adenosquamous carcinoma (as) were significantly higher than that of normal controls (P less than 0.01, P less than 0.001, P less than 0.001 and P less than 0.001, respectively), and those of tub2, por and as were also significantly higher than those of BDA, FEH and PHDP, whereas that of well differentiated tubular adenocarcinoma (tub1) was not different from those of BDA, FEH, PHDP and normal controls, and that of pap was not different from those of BDA, FEH and PHDP. The mean numbers of AgNORs of BDA and FEH were not different from that of normal controls, whereas that of PHDP was significantly higher than that of normal controls (P less than 0.01). Interestingly, the mean AgNOR counts of tubular adenocarcinoma were increased with histologic tumor grades.(ABSTRACT TRUNCATED AT 250 WORDS)