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.