Nucleolar grading of breast cancer. Comparative studies on frequency and localization of nucleoli and histology, stage, hormonal receptor status and lectin histochemistry

The impact of ribosome biogenesis in cancer: from proliferation to metastasis

The dysregulation of ribosome biogenesis is a hallmark of cancer, facilitating the adaptation to altered translational demands essential for various aspects of tumor progression. This review explores the intricate interplay between ribosome biogenesis and cancer development, highlighting dynamic regulation orchestrated by key oncogenic signaling pathways. Recent studies reveal the multifaceted roles of ribosomes, extending beyond protein factories to include regulatory functions in mRNA translation. Dysregulated ribosome biogenesis not only hampers precise control of global protein production and proliferation but also influences processes such as the maintenance of stem cell-like properties and epithelial-mesenchymal transition, contributing to cancer progression. Interference with ribosome biogenesis, notably through RNA Pol I inhibition, elicits a stress response marked by nucleolar integrity loss, and subsequent G1-cell cycle arrest or cell death. These findings suggest that cancer cells may rely on heightened RNA Pol I transcription, rendering ribosomal RNA synthesis a potential therapeutic vulnerability. The review further explores targeting ribosome biogenesis vulnerabilities as a promising strategy to disrupt global ribosome production, presenting therapeutic opportunities for cancer treatment.

PPM1D controls nucleolar formation by up-regulating phosphorylation of nucleophosmin

An increase of nucleolar number and size has made nucleoli essential markers for cytology and tumour development. However, the underlying basis for their structural integrity and abundance remains unclear. Protein phosphatase PPM1D was found to be up-regulated in different carcinomas including breast cancers. Here, we demonstrate for the first time that PPM1D regulates nucleolar formation via inducing an increased phosphorylation of the nucleolar protein NPM. We show that PPM1D overexpression induces an increase in the nucleolar number regardless of p53 status. We also demonstrated that specific sequential phosphorylation of NPM is important for nucleolar formation and that PPM1D is a novel upstream regulator of this phosphorylation pathway. These results enhance our understanding of the molecular mechanisms that govern nucleoli formation by demonstrating that PPM1D regulates nucleolar formation by regulating NPM phosphorylation status through a novel signalling pathway, PPM1D-CDC25C-CDK1-PLK1.

Image analysis of the AgNOR response in ras-transformed human breast epithelial cells

The argyrophylic staining of the nucleolar organizer regions (AgNOR positive response) in interphase nuclei is often related directly to the cellular demand for ribosome biogenesis and is considered of relevance in studies of tumor pathology. Transformation of human breast epithelial MCF-10A cells by the c-Ha-ras oncogene results in altered growth, invasiveness and tumorigenicity in nude mice. Since ras transformation may be associated with a more intense nucleolar activity, we examined the influence of transfection by the Ha-ras oncogene on AgNOR staining response in MCF-10A cells. Following assessment of the AgNOR response with video image analysis, the AgNOR-positive areas and the AgNOR area/nuclear area ratio, but not the number of AgNOR aggregates or dots per nucleus, were found to be much higher after ras transformation. A role of the Ha-ras transformation on the nucleolar activity of the MCF-10A is thus suggested as assessed by the AgNOR staining. Based on data in the literature, it is also hypothesized that a decreased wild-type p53 level, possibly promoted by the ras transformation, may be associated with the increased AgNOR response.

Biomarkers in breast cancer

Breast cancer is one of the most frequently diagnosed cancers among women in the western world. Due to the aggressive behaviour of some specific types and the possibility of an early diagnosis, breast cancer has been constantly studied. Tumour size, histological type, cellular and nuclear characteristics, mitotic index, vascular invasion, hormonal receptors and axillary lymph node status are biomarkers routinely used. However, these parameters are not enough to predict the course of this disease. Molecular biology advances have made it possible to find new markers, which have already been incorporated to the clinical practice. Their ultimate goal is to reduce mortality by identifying women at risk for the development of this disease, help diagnosis, determine prognosis, detect recurrences, monitor and guide treatment, and in particular cancers they are suited for general screening. Tumour markers in breast cancer were ranked in categories reflecting their clinical utility, according to the American College of Pathologists.

This article focuses on traditional and new molecular markers stratifying them into categories and emphasizing their relevance in the routine evaluation of patients with breast cancer.

Comparing the importance of prognostic factors in Cox and logistic regression using SAS

Two SAS macro programs are presented that evaluate the relative importance of prognostic factors in the proportional hazards regression model and in the logistic regression model. The importance of a prognostic factor is quantified by the proportion of variation in the outcome attributable to this factor. For proportional hazards regression, the program %RELIMPCR uses the recently proposed measure V to calculate the proportion of explained variation (PEV). For the logistic model, the R(2) measure based on squared raw residuals is used by the program %RELIMPLR. Both programs are able to compute marginal and partial PEV, to compare PEVs of factors, of groups of factors, and even to compare PEVs of different models. The programs use a bootstrap resampling scheme to test differences of the PEVs of different factors. Confidence limits for P-values are provided. The programs further allow to base the computation of PEV on models with shrinked or bias-corrected parameter estimates. The SAS macros are freely available at www.akh-wien.ac.at/imc/biometrie/relimp

Significance of the expression of proliferation-associated nucleolar antigen p120 in human colorectal tumors

Nucleolar protein p120 is considered to be associated with cell proliferation and has also been detected in a broad range of human malignant cells and tissues, but not in either normal resting tissue or most benign tumors. To clarify the significance of the expression of p120 in colorectal tumors or to evaluate the contribution of p120 in the development of colorectal carcinoma, the authors developed a monoclonal antibody against p120 and then examined its expression in adenoma, carcinoma, and normal mucosa. In adenomas, p120 expression was shown in none of 13 cases of mild dysplasia (0%), 2 of 15 of moderate dysplasia (13.3%), and in 2 cases of severe dysplasia (100%). p120-positive adenomas of moderate dysplasia tended to be larger and had higher Ki-67 indexes than the negative ones (adenomas of moderate dysplasia). All 27 carcinomas were positive for p120. p120 immunostaining was found in the nuclei and corresponded closely to the prominent nucleoli of tumor cells. In contrast, either weak or the occasional expression of p120 was traced in only one of the nine normal mucosae (11.1%). Three of the transitional mucosae of the carcinoma were also positive for p120. The percentage of p120-positive tumor cells (p120 index) ranged from 3.2% to 86.6%, and the mean p120 indexes of the four adenomas and all carcinomas were 21.3% and 41.5%, respectively. The p120 index was significantly related to the Ki-67 index (P < .001) in the p120-positive tumors, whereas the p120 index of the carcinoma did not significantly correlate to the known prognostic markers, such as tumor size, stage, or the degree of differentiation. These results thus suggest that the expression of p120 serves as a marker for cells with a high proliferative potential and is linked to the late events of colorectal tumor progression.

Prognostic value of proliferating cell nuclear antigen and c-erbB-2 compared with conventional histopathological factors in breast cancer

Expression of proliferating cell nuclear antigen (PCNA) and c-erbB-2 oncoprotein has been assessed in 471 women with breast cancer to evaluate their prognostic value as compared to conventional histopathological factors. In univariate analysis, high PCNA expression (> or = 20%) predicted a significantly worse survival in lymph-node-negative tumors (univariate P = 0.031). However, the effect disappeared in multivariate analysis and the histological grade remained the only independent factor for this group. Despite its close correlation to histological grade (P < 0.001), PCNA expression discriminated subsets with different survival within the heterogeneous group of moderately differentiated tumors (univariate P = 0.073, multivariate P = 0.075). PCNA expression was not found to be a significant prognostic factor in lymph-node-positive tumors, thus it was of limited value for breast cancer patients as a whole. c-erbB-2 protein overexpression was associated with a worse survival (univariate P = 0.019, multivariate P = 0.057) for the entire group of patients. The effect was mainly attributed to the significance of c-erbB-2 as an independent factor in lymph-node-positive (up to three nodes, multivariate P = 0.04; four or more nodes: multivariate P = 0.017) and large tumors (> 2 cm: multivariate P = 0.002). c-erbB-2 was without significance in lymph-node-negative patients. Though both factors might amplify the prognostic information for distinct patient subsets they do not achieve the strong prognostic value of conventional histopathological features in breast cancer.

Nucleolar and argyrophilic nucleolar organizer region counts in urothelial carcinomas with special emphasis on grade II tumors

Prognostic assessment of bladder carcinomas of intermediate differentiation is difficult. This study therefore investigated the prognostic values of nucleolar status and silver staining of argyrophilic nucleolar organizer regions (AgNORs) in grade II bladder carcinomas. In biopsies from 34 grade II transitional cell carcinomas of the urinary bladder the number of nuclei with nucleoli, the location of nucleoli within the nucleus and the number of AgNORs were determined in 1000 or 200 nuclei per section respectively. Ten biopsies showing normal urothelium, 18 cases with mild to severe atypia, 27 grade I, 34 grade II and 12 grade III transitional cell carcinomas were also studied. Significantly differing nucleolar and AgNOR values were found comparing normal urothelium/grade I carcinomas with severe urothelial atypia/grade III carcinomas. Grade II carcinomas, however, were inhomogeneous. One subgroup had nucleolar and AgNOR values resembling grade I carcinomas while the second group had values similar to those of grade III carcinomas. This subdivision of grade II carcinomas correlates with results reported for DNA-cytometry. The results suggest a subdivision of patients with grade II transitional cell carcinomas into a low risk and high risk group.

Coiled bodies in the nucleolus of breast cancer cells

Coiled bodies are a special type of small round nuclear body, composed of coiled fibers and granules, especially prominent in the nucleoplasm of highly active cells (Brasch and Ochs (1992) Exp. Cell Res. 202, 211–223). Although no specific function has been assigned to coiled bodies, they contain spliceosome snRNAs and proteins, as well as the nucleolar U3 RNA-associated protein fibrillarin. In the present study, we have used antibodies to the coiled body-specific protein p80-coilin, together with double-label immunofluorescence, confocal microscopy and immunoelectron microscopy, to examine the distribution of coiled bodies in a number of different breast cancer cell lines. By immunofluorescence, all cell lines had prominent coiled bodies in the nucleoplasm and several cell lines appeared to have coiled bodies within the nucleolus itself. Double-label immunofluorescence and confocal laser scanning microscopy confirmed the nucleolar localization of coiled bodies. Besides containing p80-coilin, nucleoplasmic and nucleolar coiled bodies contained fibrillarin and Sm proteins. By conventional and immunoelectron microscopy, nucleolar coiled bodies appeared as discrete structures within the nucleolus in a number of different morphotypes, distinct from the normal nucleolar domains of granular component, dense fibrillar component, and fibrillar centers. While the significance of finding coiled bodies in the nucleolus of certain breast cancer cell lines is at present unknown, this represents the first report of coiled bodies and Sm staining in the nucleolus of mammalian cells.

Expression of beta-1 integrins on tumor cells of invasive ductal breast carcinoma

The integrins are transmembrane alfabeta heterodimers mediating cell-cell as well as cell-extracellular matrix interactions. The present study was designed to analyse the expression of beta-1 integrins on cryostat sections of invasive ductal carcinomas not otherwise specified by avidin-biotin complex immunoperoxidase technique, and to compare it with the morphometric prognostic index (MPI). The results show that the expression of beta-1 integrins is heterogeneous in the tumors. This heterogeneity was observed in quantitative and qualitative staining pattern. There was an absent expression of beta-1 integrins in 22 out of 55 tumors while 33 showed staining, weak on 23 cases and strong on 10 infiltrative ductal carcinomas. Statistical analysis pointed to some correlation of beta-1 integrins with some morphometric parameters. Low or absent expression of beta-1 integrins correlated significantly with tumors exceeding 2 cm (p < 0.0245). Moreover, a larger proportion of tumors with positive lymph nodes showed absence of beta-1 expression compared with negative lymph node, and this was also statistically significant (p < 0.0076). Correlation between mitotic activity index and staining intensity for beta-1 integrins was not found (p < 0.372). When tumors with different beta-1 expression were subdivided according to MPI values into two groups, one group with a low-risk, < 0.6, and second with a high risk, > 0.6, concordance in prognostic value was shown between MPI and beta-1 expression (p < 0.0193). These results support the idea that loss of beta-1 integrins correlates with the invasive and metastatic potential of tumor cells.

Relationship between interphase AgNOR distribution and nucleolar size in cancer cells

We have studied the relationship between interphase nucleolar organizer region (NOR) distribution and nucleolar size in cancer cells at light-microscopical level. Thirteen cases of formalin-fixed bladder cancer and fifteen cases of methacarn-fixed tumours of different origin were used. Nucleoli of the former cases were stained by Phloxine B and of the latter by Toluidine Blue. Selective visualization of interphase NORs was obtained by carrying out the one-step silver staining reaction for AgNOR proteins (Ploton et al., 1986). The area occupied by Phloxine B- or Toluidine Blue-stained nucleoli and interphase silver-stained NORs was measured by means of an automated image analyser. Both in bladder cancers and in the other tumour lesions nucleolar and interphase AgNOR areas were linearly related (r = 0.95 and r = 0.96, respectively, P < 0.001). The close relationship between the area of nucleoli and that of silver-stained nucleolar structures was maintained even if the silver-staining procedure was prolonged beyond the optimal time length for selective interphase NOR staining. In the latter case, however, single interphase AgNORs were no longer visible within the nucleolar body which was, in fact, homogeneously stained. These data indicate that evaluation of the interphase AgNOR area has the same relevance, in tumour pathology, as whole nucleolar size measurement.

Will a tumor metastasize? Quantitate, semi-quantitate or pseudo-quantitate? A brief review of the microscopic prediction of tumor metastasis

This review examines ways in which histopathologists can attempt to predict whether a neoplasm will metastasize by microscopic examination of surgically removed samples of human neoplasms. These include qualitative description, semi-quantitative analysis of differentiation and proliferation, or of the nature of the edge of the neoplasm, and quantitative analysis of mitotic counts. More recently measurement of DNA content, analysis of DNA turnover, measurement of proliferation antigens, measurement of nucleolar organizing areas, counting nucleoli, morphometry of nuclei and identification of genetic change have become possible. There is no test capable of uniform accurate prediction of prognosis. In certain types of neoplasms in individual sites useful prognostic information can be obtained either by rigorous semi-quantitative microscopic analysis or by quantitative microscopical analysis. There is still doubt as to whether newer quantitative techniques will perform uniformly better than older semi-quantitative techniques. The simple subjective statement "high-grade malignancy, average malignancy, low malignancy" is better than elaborate non-reproducible pseudo-quantitation.

Morphometric studies for objective diagnosis of intraductal carcinoma of the breast

In order to obtain objective histologic criteria for distinguishing intraductal carcinomas of the breast from benign intraductal hyperplasia, a morphometric study was carried out on 15 cases of breast carcinoma (5 cases of comedo carcinoma, 5 cribriform carcinoma and 5 papillotubular carcinoma) and 10 benign control lesions (5 papilloma and 5 fibrocystic disease). Morphometric analysis was performed for each group with regard to 1) mean nuclear area, 2) mean nucleolar size, 3) mitotic index, and 4) nuclear count within predefined area (nuclear density) in histologic specimens. The results obtained were as follows: 1) Mean nuclear area for comedo carcinoma was distinctively large. This, together with its coefficiency variance, may be a good indicator for identifying this type of carcinoma. 2) Mean nucleolar size was significantly larger in each carcinoma group than in their benign counterparts. Nucleolar size was therefore considered to be the most reliable parameter for discriminating malignant cells from benign hyperplasia. 3) Mitotic index was relatively high in comedo and papillotubular carcinomas. 4) No difference was seen in nuclear density between the malignant and benign groups. In addition to the major criteria, combined application of these morphometric indicators might also be helpful for practical histologic assessment.

The impact of nucleolar organizer regions for the lymph node spread and prognosis of invasive ductal mammary carcinoma

In primary tumours of 40 patients with invasive ductal carcinomas the significance of nucleolar organizer regions (NORs) for metastatic spread to the axillary lymph nodes and for the prognosis was assessed. Silver-stained tissue sections were investigated by means of semiautomated image analysis. The nucleolar organizer regions of 100 tumour cell nuclei per specimen were measured. The number as well as the area of the NORs were evaluated together with morphometrical and DNA features, histopathological and clinical data. By means of multivariate discriminant analysis, significant differences between tumours of 20 node-negative and 20 node-positive patients could be found. The mean number of NORs was significantly higher in patients with lymph node metastases (p = 0.0059), whereas the mean area was significantly lower in node-positive patients. By using the NOR number as the only parameter both groups were classified with an overall efficiency of 95%. There was also a significant difference between long-term and short-term survivors by considering the mean number of NORs, but the Auer-type, the 2 cDl value, and the DNA-grade of malignancy were of better predictive value. Within the group of node-negative patients the NOR number was most suitable for distinguishing between good and poor prognosis, whereas within the group of node-positive patients once more the DNA parameters played the most decisive role for predicting prognosis. With regard to the small number of patients the results have to be considered as preliminary. Further investigations in a more extensive population are necessary.

How malignant is malignant? A brief review of the microscopic assessment of human neoplasms, and the prediction of whether they will metastasize and kill

This review examines ways in which histopathologists can attempt to predict the degree of malignancy from the microscopic examination of surgically removed samples of human neoplasms. These include mitotic counts, measurement of DNA content, analysis of DNA turnover, measurement of proliferation antigens, measurement of nucleolar organizing areas, counting nucleoli, morphometry of nuclei, identification of genetic change, measurement of lysis of basement membrane, and measurement of invasion in vitro. The latter two are not currently of practical value. Of the rest none is uniformly capable of predicting the degree of malignancy of a human neoplasm. After further refinement and control measurement of several such parameters may however contribute more to the prediction of malignancy than present subjective assessments.

Histological changes in Dunning prostate tumors and testes of rats treated with LH-RH antagonist SB-75

Rats bearing Dunning R-3327 hormone-dependent prostate tumors were treated with LH-RH antagonist SB-75 in the form of microcapsules for sustained delivery administered every 3 weeks and which released 24, 48, 72 micrograms/day respectively. The effects were compared with those of microcapsules of the agonist D-Trp-6-LH-RH releasing 25 micrograms/day. Both types of LH-RH analogs significantly inhibited tumor growth over a period of treatment lasting 8 weeks. The effect of SB-75 was dose-dependent. The total inhibition of spermatogenesis, as well as atrophic signs in the prostate and seminal vesicles, demonstrated a marked suppression of the pituitary-gonadal system by these analogs. The histological signs of tumor regression were analyzed. The vascular content of tumors did not change after the treatments, but an increased amount of connective tissue was found in the treated tumors, especially after administration of SB-75. Both the agonist and the antagonist caused a moderate decrease of the number of mitotic cells and a marked increase of apoptosis in the tumors. The apoptotic index, i.e. the percentage of tumorous glands showing signs of apoptosis, reached 40-50% in treated groups, compared to only 15% in controls. An apoptotic index of 60% was noted in a separate group of rats treated with 200 micrograms SB-75/animal/day for 3 days. The signs of enhanced apoptosis disappeared 1 week after the short-term treatment. The induction of apoptosis by LH-RH analogs seemed to be of greater importance in tumor growth inhibition than their antimitotic effect. These results extend our previous observations on the efficacy of LH-RH antagonists in inhibition of various cancers. This histopathologic evaluation clearly supports our contention that modern antagonists of LH-RH, free of edematogenic effects, inhibit the growth of Dunning prostate tumors. Because of the immediate inhibitory effects, the use of LH-RH antagonists might lead to an improvement in the clinical response in patients with prostate cancer.