Nuclear DNA content and nucleolar organizer regions in colorectal cancer

Prognostic Significance of Two Dimensional AgNOR Evaluation in Local Advanced Rectal Cancer Treated with Chemoradiotherapy

The prognostic significance of AgNOR proteins in stage II-III rectal cancers treated with chemoradiotherapy was evaluated. Silver staining was applied to the 3μm sections of parafin blocked tissues from 30 rectal cancer patients who received 5-FU based chemoradiotherapy from May 2003 to June 2006. The microscopic displays of the cells were transferred into the computer via a video camera. AgNOR area (nucleolus organizer region area) and nucleus area values were determined as a nucleolus organizer regions area/total nucleus area (NORa/ TNa). The mean NORa/TNa value was found to be 9.02±3.68. The overall survival and disease free survival in the high NORa/TNa (>9.02) patients were 52.2 months and 39.4 months respectively, as compared to 100.7 months and 98.4 months in the low NORa/TNa (<9.02) cases. (p<0.001 and p<0.001 respectively). In addition, the prognosis in the high NORa/TNa patients was worse than low NORa/TNa patients (p<0.05). In terms of overall survival and disease-free survival, a statistically significant negative correlation was found with the value of NORa/TNa in the correlations tests. Cox regression analyses demostrated that overall survival and disease-free survival were associated with lymph node status (negative or positive) and the NORa/TNa value. We suggest that two-dimensional AgNOR evaluation may be a safe and usable parameter for prognosis and an indicator of cell proliferation instead of AgNOR dots.

Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999

BACKGROUND

Under the auspices of the College of American Pathologists, the current state of knowledge regarding pathologic prognostic factors (factors linked to outcome) and predictive factors (factors predicting response to therapy) in colorectal carcinoma was evaluated. A multidisciplinary group of clinical (including the disciplines of medical oncology, surgical oncology, and radiation oncology), pathologic, and statistical experts in colorectal cancer reviewed all relevant medical literature and stratified the reported prognostic factors into categories that reflected the strength of the published evidence demonstrating their prognostic value. Accordingly, the following categories of prognostic factors were defined. Category I includes factors definitively proven to be of prognostic import based on evidence from multiple statistically robust published trials and generally used in patient management. Category IIA includes factors extensively studied biologically and/or clinically and repeatedly shown to have prognostic value for outcome and/or predictive value for therapy that is of sufficient import to be included in the pathology report but that remains to be validated in statistically robust studies. Category IIB includes factors shown to be promising in multiple studies but lacking sufficient data for inclusion in category I or IIA. Category III includes factors not yet sufficiently studied to determine their prognostic value. Category IV includes factors well studied and shown to have no prognostic significance.

MATERIALS AND METHODS

The medical literature was critically reviewed, and the analysis revealed specific points of variability in approach that prevented direct comparisons among published studies and compromised the quality of the collective data. Categories of variability recognized included the following: (1) methods of analysis, (2) interpretation of findings, (3) reporting of data, and (4) statistical evaluation. Additional points of variability within these categories were defined from the collective experience of the group. Reasons for the assignment of an individual prognostic factor to category I, II, III, or IV (categories defined by the level of scientific validation) were outlined with reference to the specific types of variability associated with the supportive data. For each factor and category of variability related to that factor, detailed recommendations for improvement were made. The recommendations were based on the following aims: (1) to increase the uniformity and completeness of pathologic evaluation of tumor specimens, (2) to enhance the quality of the data needed for definitive evaluation of the prognostic value of individual prognostic factors, and (3) ultimately, to improve patient care.

RESULTS AND CONCLUSIONS

Factors that were determined to merit inclusion in category I were as follows: the local extent of tumor assessed pathologically (the pT category of the TNM staging system of the American Joint Committee on Cancer and the Union Internationale Contre le Cancer [AJCC/UICC]); regional lymph node metastasis (the pN category of the TNM staging system); blood or lymphatic vessel invasion; residual tumor following surgery with curative intent (the R classification of the AJCC/UICC staging system), especially as it relates to positive surgical margins; and preoperative elevation of carcinoembryonic antigen elevation (a factor established by laboratory medicine methods rather than anatomic pathology). Factors in category IIA included the following: tumor grade, radial margin status (for resection specimens with nonperitonealized surfaces), and residual tumor in the resection specimen following neoadjuvant therapy (the ypTNM category of the TNM staging system of the AJCC/UICC). (ABSTRACT TRUNCATED)

American Joint Committee on Cancer Prognostic Factors Consensus Conference: Colorectal Working Group

BACKGROUND

The American Joint Committee on Cancer (AJCC), which regularly reviews TNM staging systems, established a working party to develop recommendations for colorectal carcinoma.

METHODS

A multidisciplinary consensus conference using published literature developed an arbitrary classification system of prognostic marker value (Category I, IIA, IIB, III, and IV), which forms the framework for this report.

RESULTS

The working party concluded that several T categories should be subdivided: pTis into intraepithelial carcinoma (pTie) and intramucosal carcinoma (pTim); pT1 into pT1a and pT1b corresponding to the absence or presence of blood or lymphatic vessel invasion, respectively; and pT4 into pT4a and pT4b according to the absence or presence of tumor involving the surface of the specimen, respectively. The working party also recommended that TNM groups be stratified based on the presence or absence of elevated serum levels of carcinoembryonic antigen (CEA) (>/= 5 ng/mL) on preoperative clinical examination. In addition, the working party also concluded that carcinoma of the appendix should be excluded from the colorectal carcinoma staging system because of fundamental differences in natural history.

CONCLUSIONS

The TNM categories and stage groupings for colorectal carcinoma published in the current AJCC manual have clinical and academic value. However, a few categories require subdivision to provide increasing discrimination for individual patients. The serum marker CEA should be added to the staging system, whereas multiple other factors should be recorded as part of good clinical practice. Although many molecular and oncogenic markers show promise to supplement or modify the current staging systems eventually, to the authors' knowledge none have yet been evaluated sufficiently to recommend their inclusion in the TNM system.

AgNOR staining and quantification

Nucleolar organiser regions (NORs) are defined as nucleolar components containing a set of argyrophilic proteins, which are selectively stained by silver methods. After silver-staining, the NORs can be easily identified as black dots exclusively localised throughout the nucleolar area, and are called "AgNORs". The NORs' argyrophilia is due to a group of nucleolar proteins, which have a high affinity for silver (AgNOR proteins). A number of studies carried out in different tumour types demonstrated that malignant cells frequently present a greater AgNOR protein amount than corresponding non-malignant cells. Moreover, in cancer tissues AgNOR protein expression was found to be strictly related to the cell duplication rate. Over the past 12 years, the "AgNOR method" has been applied in tumour pathology for both diagnostic and prognostic purposes. However, the lack of a standardised silver-staining protocol has led to much misinterpretation of actual structures evaluated in individual studies. Indeed, the absolute AgNOR scores reported by different authors for the same types of tumour are scarcely comparable and the results produced by these investigations sometimes seem to be conflicting. In order to achieve definitive standardisation of the AgNOR method and produce comparable data in all laboratories, the "International Committee on AgNOR Quantitation" was founded, and during the first Workshop "AgNORs in Oncology" held in Berlin in 1993 guidelines for AgNOR protein evaluation were first defined. The present paper discusses the main technical aspects of NOR silver-staining, and critically evaluates the methods commonly employed for AgNOR protein quantification in routine cyto-histopathology.

Proliferation of hepatic metastases of colorectal carcinoma: relationship to primary tumours and prognosis after hepatic resection

In this study, we determined the proliferation indices of liver metastatic tumours originating from colorectal carcinomas using Ki67 and argyrophil nucleolar organizer region associated proteins (AgNOR) stain. We examined the primary and metastatic tumours in 27 patients with liver metastasis and eight cases with non-metastatic colorectal carcinoma as a control.The number of AgNOR dots in metastatic tumours was significantly higher than in the respective primary tumours of the metastasis group or in non-metastatic colorectal carcinomas. The Ki67 labelling index was similar in all groups. The Ki67 labelling index and AgNOR counts did not correlate with each other. There was no significant relationship between proliferation indices and the duration of the disease-free period following hepatic resection for metastases or with prognosis after hepatectomy. We conclude that Ki67 and AgNOR are not useful indicators of prognosis in patients who undergo operation for liver metastasis of colorectal carcinomas.

Evaluation of argyrophilic nucleolar organizer region and proliferating cell nuclear antigen in colorectal cancer

BACKGROUND AND OBJECTIVES

Information on cellular proliferation is gaining importance for predicting prognosis in several cancers. To clarify the clinicopathological significance of argyrophilic nucleolar organizer region (AgNOR), proliferating cell nuclear antigen (PCNA), and DNA ploidy pattern, we studied their correlations with clinicopathological factors in colorectal cancer.

METHODS

Fifty-two patients with colorectal cancer were examined by AgNOR staining, immunohistochemical study of PCNA expression, and DNA flow cytometry.

RESULTS

The AgNOR score and the PCNA labeling rate (PCNA LR) were significantly higher in patients with deep invasion (P = 0.0072, P = 0.0355), liver metastasis (P = 0.0022, P = 0.0001), and Dukes D classification (P = 0.0002, P = 0.0001) than in patients without these factors. In patients with high AgNOR score (>3.83) or with high PCNA LR (>48.8), prognosis was significantly worse (P = 0.0002, P = 0.0123) than in those with low AgNOR score (<3.83) or in those with low PCNA LR (<48.8), respectively. No significant association was observed between AgNOR score and PCNA LR. Combined analysis revealed that the survival curve for patients with high AgNOR score and high PCNA LR was significantly lower (P = 0.0156) than that for patients with high AgNOR score and low PCNA LR. There was no significant correlation between DNA ploidy pattern and clinicopathological findings.

CONCLUSIONS

PCNA LR and AgNOR score were correlated not only with local progression but also with metastasis. Their determination provided useful prognostic information, and these parameters are probably independent. Their simultaneous determination was useful for accurate evaluation of prognosis. The value of DNA ploidy pattern was uncertain.