Nucleolar organizer regions, proliferative activity and DNA index in gastric carcinoma

NO38 expression and nucleolar counts are correlated with cellular DNA content but not with proliferation parameters in colorectal carcinomas

AIMS

To investigate the expression of nucleolar protein NO38, to determine the numbers of nucleoli per cell, and to examine the relations of these nucleolar parameters to tumour DNA index, total cellular DNA content, S phase fraction, and Ki67 labelling index.

METHODS

36 colorectal tumours and 14 normal mucosas were studied. An anti-NO38 monoclonal antibody, 31A12, and flow cytometric analysis were used to detect expression of NO38 by means of a biotin-streptavidin-FITC (fluorescein isothiocyanate) staining method. Nucleolar counts were determined using fluorescence microscopy. Flow cytometry was used to determine tumour DNA indices and the sizes of the S phase fractions. Ki67 labelling indices were determined from tissue sections stained immunohistochemically with the MIB-1 antibody against the Ki67 nuclear protein.

RESULTS

Generally, tumour cell nucleoli were larger and more irregular in shape compared with nucleoli in normal mucosal cells. DNA aneuploid and diploid tumours expressed 2.8 and 2.1 times more NO38 than normal mucosa. The mean (SD) values for nucleolar counts were higher for the DNA aneuploid tumours (3.81 (0.93)) than the diploid tumours (2.62 (0.38)) and normal mucosa (2.34 (0.37)). NO38 expression and numbers of nucleoli correlated significantly (r = 0.52, p = 0.01). There were, however, no significant correlations between these nucleolar parameters and either the sizes of tumour S phase fractions or Ki67 labelling indices. Cell cycle resolved expression of NO38 in tumours and normal mucosa demonstrated that expression increased approximately in proportion to the DNA content throughout the cell cycle. In aneuploid tumours, NO38 expression was 43% and 98% higher in S and G2 phases, respectively, compared with the G1 phase. Sorting of these populations revealed that the nucleolar count also increased as the DNA content increased but by only 29% and 47% in S and G2, respectively. Apoptotic cells lacked NO38.

CONCLUSIONS

NO38 expression is higher in tumours than in normal mucosa owing to the increased DNA content and larger nucleoli in tumours; expression increases proportionally with DNA content as cells progress through the cell cycle from G1 through S and G2. However, NO38 expression does not correlate with the tumour S phase fraction or Ki67 labelling index and is lost during apoptosis. Also the results suggest that nucleoli grow in size during the cell cycle, which would account for the doubling of NO38 expression from G1 to G2, as the nucleolar count increased by only 47%.

Renal cell carcinoma: Pathological prognostic criteria

– Pathological criteria so far employed in the prognosis of renal cell carcinoma provide no clinically useful information. This paper emphasises the possibilities offered by histopathology today for tackling this clinical problem more effectively. Nuclear analysis, with objective and quantitative evaluation of the degree of distortion, may provide extremely useful information. The authors correctly classified 90% of the 50 cases of renal cell carcinoma considered and whose follow-up at 5 years was known.

Are argyrophilic nucleolar organizer regions good prognostic indicators of survival of patients with esophageal cancer with lymph node metastasis?

Argyrophilic nucleolar organizer regions (AgNORs) were evaluated in 95 samples from primary esophageal squamous cell carcinomas and 75 samples from metastatic lymph nodes. The number of AgNORs per nucleus in primary tumors with positive nodes (n=53, 6.1+/-1.8) was greater than that in primary tumors with negative nodes (n=42, 3.8+/-1.1, P<0.001). In 39 of 53 patients with positive nodes, the numbers of AgNORs per nucleus in metastatic lymph nodes were lower than those in primary tumors. The 5-year survival rate of these patients was 23.7%. However, the numbers of AgNORs per nucleus in metastatic lymph nodes were greater than those of primary tumors in 14 of 53 patients with positive nodes, and 11 of these 14 patients died from recurrence of cancer within 3 years after surgery. These observations suggest that the proliferative activity of cancer cells might be suppressed in the regional lymph nodes. However, cancer cells with higher proliferative activity in the regional lymph nodes than in the primary tumors might overcome immunological defenses and subsequent further metastasis might occur.

Lymphatic invasion and potential for tumor growth and metastasis in patients with gastric cancer

BACKGROUND

Lymph node metastasis is a risk factor for the occurrence of peritoneal dissemination and liver metastasis in patients with gastric cancer.

METHODS

We analyzed data on 324 patients with serosally invasive gastric cancer with respect to the relation between lymphatic invasion and potential for tumor growth and metastasis. All these patients were curatively treated in the Department of Surgery II, Kyushu University.

RESULTS

Lymphatic invasion was evident in 214 patients, in whom vascular invasion was more frequent and the rate of lymph node metastasis was higher compared with patients with no lymphatic invasion. There was no difference in tumor size. The type of recurrence varied, and the prognosis was poor in patients with lymphatic invasion. The DNA ploidy pattern was higher, and the levels of proliferating cell nuclear antigen labeling and argyrophilic nucleolar organizer regions count were significantly higher in tumor tissues with lymphatic invasion than in those without invasion.

CONCLUSIONS

Gastric cancers with characteristics of lymphatic invasion have higher proliferating activities, and metastases to distant organs are likely.

Evaluation of testicular germ cell tumor proliferation using DNA flow cytometry and nucleolar organizer silver staining

We studied 41 testicular germ cell tumors (TGCT) using DNA flow cytometry and argyrophilic (silver staining) nucleolar organizer region (Ag-NOR) quantitation to evaluate the proliferative characteristics of TGCT and the significance of those analytical techniques. In nonseminomatous germ cell tumor (NSGCT), the percentage of S + G2M phase cells (%S + G2M) in DNA aneuploid tumor was higher than in DNA of diploid tumors. Likewise, in NSGCT the aneuploid Ag-NOR sites per nucleus (Ag-NOR count) were significantly higher in DNA aneuploid than in DNA diploid tumors. There was also a significant linear correlation between % S + G2M phase cells and the Ag-NOR count in TGCT. However, the DNA ploidy pattern and the % S + G2M phase cells, and Ag-NOR counts, did not correlate significantly with the patient survival rate or clinical stage. In conclusion, our study suggests that Ag-NOR enumeration is an effective technique for assessing cellular proliferative activity that is somewhat less expensive than DNA flow cytometry.