Thymidine labeling index and Ki-67 growth fraction in breast cancer: comparison and correlation with prognosis

Ki-67 is a prognostic parameter in breast cancer patients: results of a large population-based cohort of a cancer registry

The proliferation marker Ki-67 is one of the most controversially discussed parameters for treatment decisions in breast cancer patients. The purpose of this study was to evaluate the routine use and value of Ki-67 as a prognostic marker, and to analyze the associations between Ki-67 and common histopathological parameters in the routine clinical setting. Data from the clinical cancer registry Regensburg (Bavaria, Germany) were analyzed. Within the total data pool of 4,692 female patients, who had been diagnosed between 2005 and 2011, in 3,658 cases Ki-67 was routinely determined. Thus, a total of 3,658 patients with invasive breast cancer were included in the present study and used for statistical analysis. Ki-67 expression was associated with the common histopathological parameters. The strongest correlation was found between grading and Ki-67 (P < 0.001). In terms of survival analyses, Ki-67 was categorized into five categories (reference category Ki-67 ≤15 %) due to a nonlinear relationship to overall survival (OS). In multivariable analysis, Ki-67 was an independent prognostic parameter both for disease-free survival (DFS) (Ki-67 > 45 %, HR = 1.96, P = 0.001) as well as for OS (Ki-67: 26-35 %, HR = 1.71, P = 0.017; Ki-67: 36-45 %, HR = 2.05, P = 0.011; Ki-67 > 45 %, HR = 2.06, P = 0.002) independent of common clinical and histopathological factors. The 5-year DFS (OS) rate was 86.7 % (89.3 %) in patients with a Ki-67 value ≤15 % compared to 75.8 % (82.8 %) in patients with a Ki-67 value >45 %. Based on the data from a large cohort of a clinical cancer registry, it was demonstrated that Ki-67 is frequently determined in routine clinical work. Ki-67 expression is associated with common histopathological parameters, but is an additional independent prognostic parameter for DFS and OS in breast cancer patients. Future work should focus on standardization of Ki-67 assessment and specification of its role in treatment decisions.

Correlation between Ki67 and breast cancer prognosis

BACKGROUND

Ki67 is an immunohistochemical proliferation marker in many types of cancer and has been widely studied among breast cancer patients mostly through retrospective studies.

METHODS

The MEDLINE/PubMed database was searched for publications with the medical subject heading 'Ki 67' and the key words 'breast', 'cancer', and 'prognosis'. We restricted our search to articles published until 2012.

RESULTS

In this review, we included 78 articles and abstracts that were accessible and available in English. An effort to further explain the role of Ki67 in the prognosis of breast cancer has been made.

CONCLUSIONS

The debate on the prognostic role of Ki67 in breast cancer is still open, although most of the studies have established a relation between Ki67 and overall and disease-free survival. Further research should be made in order to establish Ki67 as a standard prognostic marker in breast cancer.

Ki-67 biomarker in breast cancer of Indian women

Background:

Biological markers that reliably predict clinical or pathological response to primary systemic therapy early during a course of chemotherapy may have considerable clinical potential.

Aims:

Aims of study to evaluated changes in Ki-67 (MIB-1) labeling index and apoptotic index (AI) before, during, and after neoadjuvant anthracycline chemotherapy in breast cancer in Indian women.

Materials and Methods:

Breast cancer tissues were collected from Grant Medical College and Sir J.J. Group of Hospitals, Mumbai, India. Twenty-seven patients receiving neoadjuvant FEC (5-fluorouracil, epirubicin, and cyclophosphamide) chemotherapy for operable breast cancer underwent repeat core biopsy after 21 days of treatment.

Results:

The objective clinical response rate was 56%. Eight patients (31%) achieved a pathological response by histopathological criteria; two patients had a near-complete pathological response. Increased day-21 AI was a statistically significant predictor of pathological response (p = 0.049). A strong trend for predicting pathological response was seen with higher Ki-67 indices at day 21 and AI at surgery (p = 0.06 and 0.06, respectively).

Conclusion:

The clinical utility of early changes in biological marker expression during chemotherapy remains unclear. Until further prospectively validated evidence confirming the reliability of predictive biomarkers is available, clinical decision-making should not be based upon individual biological tumor biomarker profiles.

Ki-67 as a prognostic molecular marker in routine clinical use in breast cancer patients

INTRODUCTION

The proliferation biomarker Ki-67 is a prognostic factor for breast cancer that has been investigated in several retrospective studies and a few prospective ones. The aims of the present study were to examine interactions between Ki-67 and other biomarkers in breast cancer patients and to assess the relationship of Ki-67 to histological grading.

PATIENTS AND METHODS

Patients with uniform immunohistochemical staining of Ki-67 by MIB-1 were identified from the database of the University Breast Center for Franconia. Data were available for 1232 of 2523 patients with invasive breast cancer who had been treated between 1998 and 2005. Ki-67 index was determined during routine work-up of the breast cancers by several surgical pathologists according to a standardized procedure. The Ki-67 proliferation index was correlated with hormone receptor status, HER2/neu status, age, tumor staging, and prognosis. In routine clinical practice, the grading was assessed according to Elston and Ellis, along with all other parameters.

RESULTS

Ki-67 proliferation index>or=20% was found to be associated with all of the prognostic factors that were tested. However, it also maintained statistical significance relative to poor overall survival in a multivariate Cox proportional hazards model (hazards ratio 1.81; 95% CI, 1.17-2.78). The hazards ratio for disease-free survival did not reach statistical significance (HR 1.41; 95% CI, 0.95-2.09; P=0.086). However, in both models the grade was not an independent prognostic factor.

CONCLUSIONS

For routine clinical purposes, grading appears to add only limited information about the prognosis in comparison with Ki-67 expression. Further investigation of quality assurance for grading and of Ki-67 as a prognostic and predictive factor is warranted.

Ki-67 as prognostic marker in early breast cancer: a meta-analysis of published studies involving 12,155 patients

The Ki-67 antigen is used to evaluate the proliferative activity of breast cancer (BC); however, Ki-67's role as a prognostic marker in BC is still undefined. In order to better define the prognostic value of Ki-67/MIB-1, we performed a meta-analysis of studies that evaluated the impact of Ki-67/MIB-1 on disease-free survival (DFS) and/or on overall survival (OS) in early BC. Sixty-eight studies were identified and 46 studies including 12 155 patients were evaluable for our meta-analysis; 38 studies were evaluable for the aggregation of results for DFS, and 35 studies for OS. Patients were considered to present positive tumours for the expression of Ki-67/MIB-1 according to the cut-off points defined by the authors. Ki-67/MIB-1 positivity is associated with higher probability of relapse in all patients (HR=1.93 (95% confidence interval (CI): 1.74–2.14); P<0.001), in node-negative patients (HR=2.31 (95% CI: 1.83–2.92); P<0.001) and in node-positive patients (HR=1.59 (95% CI: 1.35–1.87); P<0.001). Furthermore, Ki-67/MIB-1 positivity is associated with worse survival in all patients (HR=1.95 (95% CI: 1.70–2.24; P<0.001)), node-negative patients (HR=2.54 (95% CI: 1.65–3.91); P<0.001) and node-positive patients (HR=2.33 (95% CI: 1.83–2.95); P<0.001). Our meta-analysis suggests that Ki-67/MIB-1 positivity confers a higher risk of relapse and a worse survival in patients with early BC.

Evaluation of Ki-67 proliferation and apoptotic index before, during and after neoadjuvant chemotherapy for primary breast cancer

INTRODUCTION

Biological markers that reliably predict clinical or pathological response to primary systemic therapy early during a course of chemotherapy may have considerable clinical potential. This study evaluated changes in Ki-67 labeling index and apoptotic index (AI) before, during, and after neoadjuvant anthracycline chemotherapy.

METHODS

Twenty-seven patients receiving neoadjuvant FEC (5-fluorouracil, epirubicin, and cyclophosphamide) chemotherapy for operable breast cancer underwent repeat core biopsy after 21 days of treatment. Tissue from pre-treatment biopsy, day 21 and surgery was analysed for Ki-67 index and AI.

RESULTS

The objective clinical response rate was 56%. Eight patients (31%) achieved a pathological response by histological criteria; two patients had a near-complete pathological response. A reduction in Ki-67 index was observed in 68% of patients at day 21 and 72% at surgery; Ki-67 index increased between day 21 and surgery in 54%. AI decreased in 50% of tumours by day 21, increased in 45% and was unchanged in one patient; 56% demonstrated rebound increases in AI by the time of surgery. Neither pre-treatment nor post-chemotherapy median Ki-67 index nor median AI at all three time points or relative changes at day 21 and surgery differed significantly between clinical or pathological responders and non-responders. Clinical responders had lower median Ki-67 indices at day 21 (11.4% versus 27.0%, p = 0.02) and significantly greater percentage reductions in Ki-67 at day 21 than did non-responders (-50.6% versus -5.3%, p = 0.04). The median day-21 Ki-67 was higher in pathological responders (30.3% versus 14.1%, p = 0.046). A trend toward increased AI at day 21 in pathological responders was observed (5.30 versus 1.68, p = 0.12). Increased day-21 AI was a statistically significant predictor of pathological response (p = 0.049). A strong trend for predicting pathological response was seen with higher Ki-67 indices at day 21 and AI at surgery (p = 0.06 and 0.06, respectively).

CONCLUSION

The clinical utility of early changes in biological marker expression during chemotherapy remains unclear. Until further prospectively validated evidence confirming the reliability of predictive markers is available, clinical decision-making should not be based upon individual biological tumour marker profiles.

Tissue microarrays for comparing molecular features with proliferation activity in breast cancer

Tissue microarrays (TMAs) are potentially suited to find associations between molecular features and clinical outcome. Enhanced cell proliferation, as measured by Ki67 immunohistochemistry, is related to poor patient prognosis in many different tumor types. Ki67 expression shows considerable intratumoral heterogeneity. It is unclear if the TMA format is suitable for the analysis of potentially heterogeneous markers because of the small size of TMA spots. We have analyzed a breast cancer TMA containing 2,517 breast tissues, including 2,222 neoplastic and 295 normal or premalignant samples, for Ki67 labeling index (Ki67 LI) and additional markers with a known relationship to Ki67 LI by immunohistochemistry (ER, PR, Bcl-2, Egfr, p16, p53) and Fluorescence in situ hybridization (HER2, MDM2, CCND1, MYC). A high Ki67 LI was linked to tumor phenotype including grade (p < 0.0001), stage (p < 0.0001), nodal stage (p = 0.0018), and patient prognosis (p < 0.0001), elevated protein levels of p53, p16 and Egfr, reduced levels of Bcl2, ER, and PR (p < 0.0001 each), as well as amplifications of HER2, MYC, CCND1 and MDM2 (p < 0.0001 each). In summary, all expected associations between Ki67 and the analyzed molecular markers could be reproduced with high statistical significance using a TMA containing only one tissue sample per tumor, measuring 0.6 mm in diameter. We conclude that associations with cell proliferation can be reliably analyzed in a TMA format.

Proliferative Activity, Apoptosis and Expression of Oestrogen Receptor and Bcl-2 Oncoprotein in Canine Mammary Gland Tumours

Samples of 39 canine mammary gland tumours (MGTs) were examined immunohistochemically for oestrogen receptor (ER-alpha), Bcl-2 protein and Ki67 antigen, and by TUNEL assay for apoptosis. ER-alpha was expressed by 80% (31/39) of the tumours, including all of the 15 benign tumours and 67% (16/42) of the malignant tumours. ER-alpha expression was greater in the benign than in the malignant tumours (P<0.01). Bcl-2 protein was detected in 62% (24/39) of the MGTs, of which 67% (10/15) were benign and 58% (14/24) malignant. No significant difference in Bcl-2 expression between benign and malignant tumours was detected. The Ki67 and TUNEL indices were greater in malignant than in benign tumours (P<0.01). Correlation analysis suggested that ER-alpha and Bcl-2 expression were related, but this observation lacked statistical significance. The levels of cell proliferation and apoptosis did not appear to be significantly correlated with the expression of Bcl-2. A positive relationship was apparent between cell proliferation and apoptosis, whilst a negative correlation between ER-alpha and cell proliferation was demonstrated. In conclusion, the suggestion of a positive correlation between ER-alpha and Bcl-2 in canine MGTs indicates that ER may be the regulator of Bcl-2 protein, as in human breast cancer. In contrast to cell proliferation and apoptosis, ER-alpha and Bcl-2 expression were greater in benign MGTs than in their malignant counterparts.

Proliferation marker Ki-67 in early breast cancer

Molecular markers have been extensively investigated with a view to providing early and accurate information on long-term outcome and prediction of response to treatment of early breast cancer. Proliferation is a key feature of the progression of tumors and is now widely estimated by the immunohistochemical assessment of the nuclear antigen Ki-67. The expression of Ki-67 correlates with other measurements of proliferation, including S-phase and bromodeoxyuridine uptake. High Ki-67 is a sign of poor prognosis associated with a good chance of clinical response to chemotherapy, but its independent significance is modest and does not merit measurements in most routine clinical scenarios. However, its application as a pharmacodynamic intermediate marker of the effectiveness of medical therapy holds great promise for rapid evaluation of new drugs.

Prognostic and predictive markers in canine tumours: rationale and relevance. A review

Cancer is one of the most common causes of death in dogs. The availability of multiple treatment modalities and novel therapeutic targets make the correct diagnosis, prognostic stratification, and the identification of treatment effect predictive factors an issue of major debate in cancer management. Selection of high and low risk patients and the type of systemic or local treatment is important in cancer management. The search for better prognostic markers and predictive factors is now focused on the molecular mechanisms which underlie tumour behaviour, such as altered cell cycle progression, proliferation, apoptosis, and angiogenesis. The ultimate goal is to identify reliable markers that can accurately diagnose and stage a tumour and predict tumour's clinical behaviour, prognosis and response to therapy. In this review, the current state of prognostication in canine tumours and promising new molecular markers are discussed. The markers are allocated to four groups according to their function: (i) proliferation markers, (ii) apoptosis, (iii) extracellular matrix and cell adhesion molecules, (iv) angiogenesis and (v) cell cycle regulators. Clinicopathological factors and histopathological grading remain the most practical parameters in decision-making. Although experimental research has shown that molecular markers have a good potential to be used as diagnostic, prognostic or predictive markers in canine tumours, insufficient evidence exists on their efficacy for routine use in veterinary oncology.

Thymidine labeling index: prognostic role in breast cancer

The aim of this study is to evaluate the prognostic role of thymidine labeling index in patients with breast cancer. Cellular proliferation rates in 155 breast cancer specimens were investigated by 3H-thymidine labeling index (3H-TLI). Median age was 47 years (range: 23-76). At presentation, 11 patients (7.1%) had stage I disease, 76 (49%) had stage II, 64 (41.3%) had stage III disease, and 4 (2.6%) had metastatic involvement. Patients were placed in 2 groups based on their proliferative indices. The cut-off level was assigned as the median TLI value of the whole group. Correlations between proliferative activity of the tumors based on 3H-TLI levels and various previously established prognostic factors, as well as the influence of proliferative activity on survival as a clinical outcome, were analyzed. The mean and median TLI values for the whole group of patients were 4.36 +/- 4.96% and 2.76% (range: 0-23.6), respectively. There was a significant association of nuclear grade with TLI (P = 0.04). Patients who were alive with no sign of disease at the final follow-up examination had a significantly lower median TLI rate than those who were either alive with disease or those who had eventually died with disease progression (3.7% versus 1.9%, respectively; P = 0.04). Patients with locally advanced disease (N2 + N3 involvement) had a significantly higher median TLI rate than those with local nodal involvement (N1) (3.4% versus 1.7%, respectively, P = 0.026). Furthermore, TLI levels showed a significant association with overall survival in patients with node-negative disease (P = 0.02). Based on the results of this study, it can be concluded that TLI plays a significant prognostic role in a subset of patients with node-negative breast cancer. Furthermore, TLI appears to have a predictive value for the clinical outcome of patients with breast cancer. These findings may justify a more aggressive therapeutic approach in patients with high TLI levels. Further large-scale, prospective studies are required before a definite conclusion can be reached.reached.

Hormonal Factors and Breast Tumor Proliferation: Do Factors that Affect Cancer Risk also Affect Tumor Growth?

BACKGROUND

Tumor cell proliferation is one of the most significant predictors of prognosis for women with breast cancer. Personal characteristics that affect hormonal exposure have been implicated in breast tumor etiology, and it is possible that they may also influence tumor cell proliferation. We examined the association between hormone-related breast cancer risk factors and breast tumor proliferation, as reflected in two proliferation measures, Ki-67 and mitotic count.

METHODS

The study population was 484 women 40 years of age and older, who were members of a managed care organization's breast cancer screening program and were diagnosed with invasive breast cancer between 1988 and 1995. The percent of Ki-67 positive tumor cells averaged over four high powered fields (Ki-67) was log transformed and analyzed in a linear regression model. Mitotic count was dichotomized into high versus low (<or=10), and analyzed in an unconditional logistic regression model with the odds ratio (OR) as the measure of association.

RESULTS

Consistent with other studies, there was a significant trend of decreased tumor cell proliferation with increasing age ( p for trend <0.05 for both measures). Higher body weight was associated with higher Ki-67 ( p for trend <0.05), but not with higher mitotic count. We found no significant associations between any reproductive factors (age at menarche, parity, age at first birth, menopausal status and age at menopause) and either measure of tumor cell proliferation. We observed an association between reduced tumor proliferation, as measured by mitotic count and former/current use of hormone replacement therapy (HRT) in comparison to never use (adjusted OR's: former HRT use: 0.40 (95% CI 0.19-0.85); current HRT use: 0.52 (95% CI 0.26-1.04).

CONCLUSION

Certain factors related to hormonal exposure that influence breast tumor etiology, for example, age, also appear to increase tumor growth. Conversely HRT use, which clearly increases breast cancer risk, may not adversely affect, and possibly may diminish cell proliferation once tumors are established.

Relationship between the thymidine labeling and Ki-67 proliferative indices in 126 breast cancer patients

Proliferative activity has been proposed as a prognostic and predictive marker for breast cancer; Ki-67 is one of the most frequently used markers to assess proliferative activity. In the current study, Ki-67 immunoreactivity was comparatively assessed, even in terms prognostic relevance, with 3H-thymidine labeling index as a reference standard for proliferation in 126 patients with stage I and II breast cancer. There was a significant but weak correlation between Ki-67 values and the 3H-thymidine labeling index (r = 0.19, P = 0.03). Analysis of variance showed that the mean 3H-thymidine labeling index values were not statistically different in terms of pathologic size (T1, T2. T3, T4), number of pathologically positive axillary nodes (neg, pos 1-3, pos > 3), and grading classes (1, 2, 3), but significantly and inversely correlated with estrogen receptor status (P = 0.033) and progesterone receptor status (P = 0.08). The Ki-67 values significantly correlated with N status (P = 0.041), estrogen receptor status (P < 0.001), progesterone receptor status (P < 0.001), and grading (P < 0.001). The median follow-up was 37 months. In terms of prognosis, Ki-67 was associated significantly with overall survival (P = 0.01) and marginally with disease-free survival (P = 0.095). A significant difference in prognosis was found for both disease-free survival (P = 0.024) and overall survival (P = 0.040) when a 3H-thymidine labeling index cut-off of 6.5% was used (P = 0.024). The results suggest that, although both are indicators of proliferative activity, 3H-thymidine labeling index and Ki-67 seem to identify breast cancers with different phenotypes.

Prognostic and predictive role of proliferation indices in adjuvant therapy of breast cancer

In breast cancer, proliferative activity represents one of the biologic processes most thoroughly investigated for its association with tumor progression. In addition to the mitotic activity component of pathologic grading systems, several proliferation indices have provided independent information on prognosis and response to specific treatments in large retrospective studies. Recently, results from treatment protocols prospectively planned to test the clinical utility of proliferative activity have indicated that tumor cell proliferation markers identify two subsets among patients with lymph node-negative cancers: 1) those at a very low risk of relapse and 2) those who will benefit from regimens including antimetabolites. Future efforts should compare the prognostic accuracy of different proliferation markers, confirm preliminary evidence of a relationship between proliferation and response to specific systemic treatments, and standardize assay techniques to facilitate their transfer to general oncology practice.

MIB-1 labeling index in feline dysplastic and neoplastic mammary lesions and its relationship with postsurgical prognosis

Samples from feline normal, dysplastic, and neoplastic mammary tissues were used to investigate the usefulness of MIB-1 labeling index (MIB-1 I) as a prognostic indicator. Forty-eight queens bearing invasive carcinomas were included in a 2-year follow-up study. Mammary lesions were classified according to the World Health Organization system, and invasive carcinomas were further graded on the basis of the degree of tubule formation, the degree of nuclear and cellular pleomorphism, and mitotic count. Additional sections were immunostained using MIB-1 antibody, and MIB-1 I was expressed as a percentage of positive nuclei. In normal mammary gland tissues, the mean MIB-1 I was <1%. A low proliferation rate was found in all mammary adenosis and in situ carcinomas, and the highest rates were observed in feline mammary hypertrophy and invasive carcinomas. Twenty-one (43.7%) of the queens bearing invasive carcinomas were still alive at the end of the trial, and 27 (56.2%) had died. The MIB-1 I was not significantly correlated with clinical outcome, age, histologic type, or grading of the tumors, but a borderline correlation was observed with invasion of lymphatic vessels. Univariate analysis showed that high MIB-1 I was also not associated with decreased overall survival, whereas the grading system of the tumors had high predictive value (P = 0.0040) for postsurgery survival. The lack of correlation between MIB-1 I and postsurgery survival suggests that this marker alone is not sufficient to determine a correct prognosis in feline mammary carcinomas, even if it is a useful proliferation marker.

Comparison between different cell kinetic variables in human breast cancer

Cell kinetics holds a prominent role among biological factors in predicting clinical outcome and response to treatment in neoplastic patients. Different cell kinetic variables are often considered as valid alternatives to each other, but the limited size of case series analysed in several studies and the lack of simultaneous determinations of all the variables on the same tumours do not justify this conclusion. In the present study, the correlation between [3H]thymidine labelling index ([3H]dT LI), flow cytometric S phase cell fraction (FCM-S) and Ki-67 immunoreactivity (Ki-67/MIB-1) was verified and the type of correlation with the most important clinical, pathological and biological patient and tumour characteristics was investigated in a very large series of breast cancer patients. Ki-67/MIB-1, FCM-S and [3H]dT LI were determined in 609, 526 and 485 patients, respectively, and all three cell proliferation indices were evaluated in parallel on the same tumour in a series of 330 breast cancer patients. All the cell kinetic determinations were performed within the context of National Quality Control Programmes. Very poor correlation coefficients (ranging from 0.37 to 0.18) were observed between the different cell kinetic variables determined in parallel on the same series of breast cancers. Moreover, Ki-67/MIB-1 and FCM-S showed a significant relationship with histological type, grade and tumour size, whereas statistically significant correlations were not observed for [3H]dT LI. In conclusion, the results show that the different cell kinetic variables provide different biological information and cannot be considered as alternatives to each other.

Immunohistologic detection of estrogen receptor alpha in canine mammary tumors: clinical and pathologic associations and prognostic significance

Eighty-nine canine mammary tumors and dysplasias of 66 bitches were investigated to determine the immunohistochemical expression of classical estrogen receptor (ER-alpha) and its clinical and pathologic associations and prognostic value. A complete clinical examination was performed and reproductive history was evaluated. After surgery, all animals were followed-up for 18 months, with clinical examinations every 3-4 months. ER-alpha expression was higher in tumors of genitally intact and young bitches (P < 0.01, P < 0.01) and in animals with regular estrous periods (P = 0.03). Malignant tumors of the bitches with a previous clinical history of pseudopregnancy expressed significantly more ER-alpha (P = 0.04). Immunoexpression of ER-alpha decreased significantly with tumor size (P = 0.05) and skin ulceration (P = 0.01). Low levels of ER-alpha were significantly associated with lymph node involvement (P < 0.01). Malignant tumors had lower ER-alpha expression than did benign tumors (P < 0.01). Proliferation index measured by proliferating cell nuclear antigen immunostaining was inversely correlated with ER-alpha scores (P = 0.05) in all tumors. Low ER-alpha levels in primary malignant tumors were significantly associated with the occurrence of metastases in the follow-up (P = 0.03). Multivariate analyses were performed to determine the prognostic significance of some follow-up variables. ER-alpha value, Ki-67 index, and age were independent factors that could predict disease-free survival. Lymph node status, age, and ER-alpha index were independent prognostic factors for the overall survival. The immunohistochemical detection of ER-alpha in canine mammary tumors is a simple technique with prognostic value that could be useful in selecting appropriate hormonal therapy.

Microvessel count, proliferating cell nuclear antigen and Ki-67 indices in gastric adenocarcinoma

The aim of the present study was to immunohistochemically investigate the prognostic value of neovascularization (expressed as microvessel count-MVC) and tumor cell proliferation (expressed as PCNA labeling index PLI and Ki-67 labeling index KLI) in gastric adenocarcinoma. Correlations with clinicopathologic features were also evaluated. Tumor specimens from 74 patients diagnosed as gastric adenocarcinoma were included in this study. Formalin fixed, paraffin embedded tissue sections stained immunohistochemically with F-VIII, PC10 and MIB-1 monoclonal antibodies. By ocular grid subdivided into 100 areas, number of microvessels and PC10, MIB-1 positive and negative cells were counted at x400 magnification. Chi-square test, Kaplan-Meier method and cox regression analysis were used for statistical analysis. The results showed that, MVC and PLI had a significant correlation with invasion and lymph node metastasis. The prognosis was significantly worse in patients with high MVC (>14 ) and with high PLI (>49%). However any relationship was not observed between KLI (38%) and clinicopathologic parameters, so KLI failed to predict the prognosis. Cox model showed that, MVC and PLI were independent prognostic variables. Ki-67 labeling index in gastric carcinomas has no prognostic relevance. However, the evaluation of microvessel count and proliferating cell nuclear antigen index in gastric carcinomas could be reliable indicators of prognosis.

Prognostic significance of Ki-67 and topoisomerase IIalpha expression in infiltrating ductal carcinoma of the breast. A multivariate analysis of 863 cases

To evaluate the prognostic relevance of Ki-67 and topoisomerase IIalpha expression in relation to tumor stage, grade, and hormone receptor content, 942 ductal infiltrating carcinomas of the breast were examined by means of the monoclonal antibodies Ki-S11 (Ki-67) and Ki-S4 (topoisomerase IIalpha). pS2, c-erbB2, and p53 were additionally considered as prognostic variables. The median follow-up time was 149 months. Eight-hundred-and-sixty-three tumors reacted with Ki-S11 and Ki-S4; the labeling indices of the two antigens were closely associated (r = 0.93). Both correlated positively with the tumor size, c-erbB2, and p53 expression, and negatively with patient age, hormone receptor content, and pS2 immunostaining. In the univariate analysis, Ki-S11 and Ki-S4 scores, nodal status, tumor size, tumor grade, and progesterone receptor content strongly predicted both overall and metastasis-free survival (p < 0.00001). Estrogen receptor status, p53, and c-erbB2 were of minor significance. Concerning overall survival, multivariate Cox regression analysis selected a Ki-S4 score >25% (p < 0.00001) next to the nodal status, and before tumor size, progesterone receptor content, and patient age. Independent predictors of the occurrence of distant metastases were nodal status, Ki-S4, tumor size, grade 1, and progesterone receptor negativity, in that order. The Ki-S11 score was of independent prognostic significance only if examined as a continuous variable. We conclude that topoisomerase IIalpha expression as assessed by monoclonal antibody Ki-S4 may add valuable information to current prognostic models for breast cancer. Its predictive value appears to be essentially related to the proliferative activity of tumor cells.

Routinely available indicators of prognosis in breast cancer

Diagnosis coupled with prognostication is the challenge for and charge of the pathologist. In this time of rapidly developing basic knowledge and increasing sophistication in the evaluation of prognostic information, there has also been an important re-evaluation of the validity, reliability, and relevance of classic histopathology. Also, the precision of and criteria for evaluating tumor size and status of regional lymph nodes is under study. Our emphasis in this review is tissue pathology and further, its practical relevance to patient management. Histopathology remains the basis of diagnosis universally; the addition of other elements will increase precision of prediction, particularly of responsiveness to individual therapies. Histologic grade may be integrated to substratify high and low stage cases into prognostically more useful subsets. Histologic types also interact with size and nodal status to predict patients with excellent prognosis. Further refinement of these parameters may occur by analysis within clinical, pathologic, or therapeutic subsets.

Prognostic and predictive value of thymidine labelling index in breast cancer

In the last few decades, much effort has been directed towards identifying the phenotypic or functional aspect of tumor cells which can contribute to a biofunctional staging for improving the accuracy of pathologic staging used for identifying patients at different risk. Among known biologic factors, the proliferative capacity of the tumor cell population, a feature common to all tumors, has been widely investigated. Several approaches have been used to measure different aspects of the cell cycle. Among these, the thymidine labeling index (TLI) represents the fraction of cells in S-phase cell fraction and is based on the active incorporation of labelled thymidine into DNA. From basic studies conducted on several thousands of patients, the TLI of primary breast cancers appears closely related to steroid receptor status and generally unrelated to pathologic stage. Retrospective analyses performed on large series of patients treated with local regional therapy alone have consistently shown the relevance of TLI value to clinical aggressiveness in terms of relapse-free survival and overall survival. Moreover, TLI is a prognostic indicator which is independent of tumor size, steroid receptors, and p53 and bc12 protein expression, and which, together with patient age and tumor size, is able to identify patients at different risk of loco-regional or distant metastases. Recently, a direct relationship between TLI and response to polychemotherapy has been shown in patients with operable and advanced breast cancers. This finding, derived from retrospective and recently confirmed in prospective clinical studies, has led to the activation of cell kinetics based therapeutic protocols for patients with node-negative and one to three node-positive operable breast cancers.

Prognostic value of vascular density and cell proliferation in breast cancer patients

We measured microvessel density and cell proliferation index in 84 breast cancers using survival analysis to find out their prognostic value. Immunohistochemistry was applied using antibody to factor VIII-related antigen as a marker for microvessels and MIB-1 antibody to stain proliferating cells. We were not able to show any difference in survival with a mean follow-up of 10.3 years between patients with high and low microvessel count or cell proliferation index. Vascular density did not correlate with the cell proliferation rate (p = 0.4). However, patient age correlated negatively with the cell proliferation index of the tumor (p = 0.0009). There was no significant difference both in microvessel count and in cell proliferation between patients with lymph node metastasis and node negative patients. This result questions the usefulness of vascular density and cell proliferation rate as prognostic markers in breast cancer.

Immunologic proliferation marker Ki-S2 as prognostic indicator for lymph node-negative breast cancer

BACKGROUND

Proper treatment of lymph node-negative breast cancer depends on an accurate prognosis. To improve prognostic models for this disease, we evaluated whether an immunohistochemical marker for proliferating cells, Ki-S2 (a monoclonal antibody that binds to a 100-kd nuclear protein expressed in S, G2, and M phases of the cell cycle), is an accurate indicator of prognosis.

METHODS

We studied 371 Swedish women with lymph node-negative breast cancer; the median follow-up time was 95 months. The fraction of tumor cells in S phase was assessed by flow cytometry, and tumor cell proliferation was measured immunohistochemically with the monoclonal antibodies Ki-S2 and Ki-S5 (directed against the nuclear antigen Ki-67). A combined prognostic index was calculated on the basis of the S-phase fraction, progesterone receptor content, and tumor size.

RESULTS

In multivariate analyses that did or did not (263 and 332 observations, respectively) include the S-phase fraction and the combined prognostic index, the Ki-S2 labeling index (percentage of antibody-stained tumor cell nuclei) emerged as the most statistically significant predictor of overall survival, disease-specific survival, and disease-free survival (all two-sided P<.0001). In the risk group defined by a Ki-S2 labeling index of 10% or less, life expectancy was not statistically significantly different from that of age-matched women without breast cancer, whereas the group with a high Ki-S2 labeling index had an increased risk of mortality of up to 20-fold.

CONCLUSIONS

Cellular proliferation is a major determinant of the biologic behavior of breast cancer. Prognosis is apparently best indicated by the percentage of cells in S through M phases of the cell cycle. Measurement of the Ki-S2 labeling index of a tumor sample may improve a clinician's ability to make an accurate prognosis and to identify patients with a low risk of recurrence who may not need adjuvant therapy.

MIB-1 labelling index is an independent prognostic marker in primary breast cancer

The proliferative activity of a tumour is considered to be an important prognostic factor in primary breast cancer. We have investigated the prognostic value of the MIB-1 labelling index in 341 patients with primary breast cancer and compared the results with the S-phase fraction in 220 patients of the same cohort. All patients were treated in one hospital and had a median follow-up of 128 months. No correlation between MIB-1 labelling and S-phase fraction could be demonstrated. MIB-1 had prognostic value for disease-free survival in the whole group of patients (P < 0.001) and in the node-negative subgroup (P < 0.001). In multivariate analysis, MIB-1 was an independent prognostic factor (P = 0.004) besides axillary lymph node status (P = 0.001). In univariate analysis high S-phase fraction was associated with decreased overall survival (P = 0.04); however, not in multivariate analysis. Moreover, S-phase fraction had a borderline prognostic significance for post-relapse survival in multivariate analysis (P= 0.08). Thus, in conclusion, the growth fraction of a tumour as determined by the MIB-1 labelling index is an important prognostic factor in patients with primary breast cancer.

The functional relationship between in vivo bromodeoxyuridine labeling index and Ki-67 proliferation index in human breast cancer

Proliferation indices are used, along with other parameters, to estimate the risk of recurrence of breast cancer for individual patients. Because it is unlikely one index will be practical for all patients, it is important to understand the relationship between various indices of proliferation. For this reason, we compared a proliferation index based on in vivo labeling of S-phase tumor cells with the thymidine analog bromodeoxyuridine (BrdUrd), to a proliferation index based on an estimate of the growth fraction with the MIB-1 antibody to the Ki-67 antigen. With informed consent, we gave 145 patients 200 mg/m2 BrdUrd intravenously just prior to surgical removal of breast cancer. On histology sections, we visually counted S-phase cells which had incorporated BrdUrd using the Br-3 antibody which is specific to DNA-incorporated BrdUrd, and we counted cells in the growth fraction using the MIB-1 antibody to the Ki-67 antigen. We found that both indices were positively correlated with tumor size, number of positive nodes, and tumor grade, and both were negatively correlated with age and estrogen-progesterone receptor positivity. Using a linear functional relationship model, we found that the best (i.e. the maximal) fit between the two indices (correlation coefficient 0.79; p < 0.0001) occurred when each index was square root transformed, as is appropriate when counts follow a Poisson distribution. When we used the median as a cutpoint for each index, the classification of 19 percent of data pairs changed depending upon which index was used. We also estimated that the Ki-67 intercept (1.02 +/- 0.25) was significantly greater than zero. We conclude that the BrdUrd index of DNA synthesis in S-phase correlates highly with the MIB-1 index of the growth fraction, and both indices correlate well with other parameters of tumor aggressiveness. Because this correlation is driven by concordance of the extremes of high and low counts, clinical comparison will be necessary to determine which is the better prognostic marker for human breast cancer.

A simple index to predict prognosis independent of axillary node information in breast cancer

BACKGROUND

Since the course of breast cancer is often unpredictable, we wished to develop a model using characteristics of the primary tumour alone to predict prognosis.

METHODS

Several tumour features were determined, and after a median follow-up duration of 65 months, multivariate analysis identified tumour size and grade, oestrogen receptor concentration, axillary lymph node metastasis and tumour cell proliferation fraction (MIB-1 count) as being independently associated with increases in risk for both relapse and death from breast cancer. A prognostic model was constructed using tumour size and grade, oestrogen receptor concentration and MIB-1 count only. A score of 1 for each was given to tumour size > 20 mm, tumour grade 2 or 3, oestrogen receptor concentration < 10 fmol/mg cytosol protein and MIB-1 count > 9%. Five groups established by assigning a combined score of 0, 1, 2, 3 or 4 for each patient were analysed for their associations with disease-free and overall survivals.

RESULTS

This preliminary model predicted 5-year survival rates of 97, 91, 85, 68 and 50% for the five groups. The model was further simplified by excluding tumour grade from the analysis. The revised model identified four risk groups with predicted 5-year survival rates of 91, 86, 66 and 52%. This model, the Adelaide prognostic index, was also able to identify four risk groups in both node-negative and node-positive patients.

CONCLUSIONS

The Adelaide prognostic index can be used to predict prognosis even in the absence of axillary lymph node information.

The cell cycle in breast cancer

Breast cancer is a heterogeneous disease regarding morphology, invasive behavior, metastatic capacity, hormone receptor expression and clinical outcome. For prediction of prognosis, tumor cell kinetics is an important feature, traditionally evaluated by estimation of cell growth-associated parameters such as mitotic index, S-phase fraction and expression of proliferation coupled proteins, for example proliferating cell nuclear antigen (PCNA) and Ki-67 antigen. Recent data indicate that deregulation of the cell cycle can occur at different levels in cancer and that the "deregulation pattern" can be of clinical significance. In the present overview we give a short description of approaches used for cell proliferation assessments, whereafter more recent data on cell cycle deregulation are discussed. Alterations of importance in breast cancer include overexpression of cyclins D1 and E, down-regulation of cyclin-dependent kinase inhibitors, such as p16, and inactivation of the retinoblastoma and p53 tumor suppressor proteins.

p53 protein expression, cell proliferation and steroid hormone receptors in ductal and lobular in situ carcinomas of the breast

p53 and c-erbB-2 expression, and their correlation with cell proliferation and steroid hormone receptors, were investigated in 121 carcinomas, 23 lobular in situ carcinomas (LCIS), 74 intraductal carcinomas (DCIS) and 24 minimal invasive carcinomas. DCIS were classified according to the EORTC classification. All markers were measured immunohistochemically on paraffin sections. None of the LCIS, 9 DCIS and 9 minimal invasive cancers showed nuclear positivity for p53. A strong association between histological type and p53 expression was found. Proliferation rates correlated with p53 expression. c-erbB-2 positivity was found in 1 LCIS, 27 DCIS and 12 minimal invasive cancers. There was a significant correlation between p53 expression and c-erbB-2. Both parameters were associated with high proliferation rate and negativity for steroid hormone receptor status. Nuclear pleomorphism could become a comparable prognostic marker in DCIS as it is for infiltrating carcinomas.

Proliferation marker MIB-1 correlates well with proliferative activity evaluated by BrdU in breast cancer: an immunohistochemical study including correlation with PCNA, p53, c-erbB-2 and estrogen receptor status

The proliferative activity of 30 cases of non-treated invasive ductal breast carcinoma was evaluated by bromodeoxyuridine (BrdU), proliferation marker (MIB-1) and proliferating cell nuclear antigen (PCNA), and the relation between these proliferation markers and histological subtype and histological grade were investigated. In addition, the association of these proliferation markers with overexpression of p53 protein, c-erbB-2 oncoprotein, estrogen receptor (ER) status and clinicopathologic findings were also examined. The BrdU labeling index (LI), MIB-1 score and PCNA labeling rate (LR) correlated with the histological grade. However, there was no statistical difference in proliferative activity among the histological subtypes. A linear strong correlation was demonstrated between BrdU LI and MIB-1 score (r = 0.732). Significant correlation was also found between BrdU LI and PCNA LR (r = 0.446); however, the relation between MIB-1 score and PCNA LR was weak. BrdU LI and MIB-1 score correlated positively with tumor size, TNM stage and overexpression of p53, and negatively with the presence of ER. PCNA LR correlated only with p53. These results indicate that MIB-1 is closely associated with BrdU in clinicopathologic findings and is a more useful tool for evaluating cell proliferation than PCNA. However, it will be necessary to consider the clinical significance of MIB-1 immunohistochemistry cautiously until further widespread clinical and pathological studies are performed.

The important prognostic value of Ki-67 expression as determined by image analysis in breast cancer

A series of 191 female breast carcinomas (with long-term follow-up) were analysed immunohistochemically (with a monoclonal MIB1 antibody) for Ki-67 (a proliferation marker) expression with special reference to well-established prognostic factors and patient survival. Expression of Ki-67 was directly related to the S-phase fraction (P < 0.0001), the volume-corrected mitotic index (P < 0.0001), histological grade (P < 0.0001), the apoptotic index (P < 0.0001), oestrogen and progesterose receptor content (P < 0.0001 for both) and p53 accumulation (P = 0.001). No correlation was found between Ki-67 expression and lymph node status (P = 0.25), metastasis at operation (n = 0.81) or tumour size (n = 0.38). The proliferation rate, as measured by image analysis of Ki-67 expression, predicted survival in the entire cohort (P = 0.001) and in axillary-lymph-node-negative (ANN) patients (P = 0.003). The difference in recurrence-free survival between the high- and low-expression groups was greatest in ANN tumours, 40% (P = 0.008). In axillary-lymph-node-positive tumours, the Ki-67 expression was not significantly related to recurrence-free survival (P = 0.723). The results of multivariate survival analysis showed that tumour size, axillary lymph node status, and mitotic index were independent prognostic factors in the entire series whereas, in ANN cases, tumour size and Ki-67 labelling were independent prognostic factors. These findings imply that Ki-67 expression could be an important prognostic determinant in breast cancer. Because of the evident loss of the predictive power of tumour size in the 1990s, the prognostic value of Ki-67 expression may even be accentuated in the currently diagnosed small breast carcinomas.

Immunohistochemical study of Cell Cycle Modulators in G(1)-S Transition in Clinical Breast Cancer Tissue

In the present study, we investigated immunolocalization of the modulators of G(1)-S transition by using monoclonal or polyclonal antibodies for each of the modulators in 65 cases of clinical breast cancer. Two prominent cyclin dependent kinase(cdk)-cyclin complexes, cdk4-cyclin D and cdk2-cyclin E, were proved to have different modes of mutual expression. cdk4-positive lesions were found to equal cyclin D-expressing lesions in 55 cases, while the former were more extensive than the latter in 9 cases. On the other hand, cyclin E expression was detected in all the cases examined and was more dominant than that of cdk2/cdc2 in as many as 40 cases whereas the reverse was seen in only 1 case. Interestingly, cdk4(P<0.01)and cyclin E(P<0.05)expressions showed an inverse relationship with the tumor size and the cancer stage. A similar tendency was also detected for two other positive modulators of G(1)-S transition, indicating that cell cycle progression must be regulated by the cancer itself once it has grown to a certain extent. p21, which has been regarded as a universal inhibitor of the cell cycle, was expressed in 43.1% of the cases examined and its immunoreactivity showed an inverse relationship with lymph node metastasis(P<0.05). It also tended to be absent more frequently in T3 or larger cancers and stage III cases. Moreover, two patients who died as a result of cancer and three patients with recurrence were all p21 negative, suggesting that p21 is prognosticably the most significant of all these modulators.

Relationship between p53 gene abnormalities and other tumour characteristics in breast-cancer prognosis

The prognostic significance of p53 gene abnormalities was investigated in 919 primary breast-cancer patients. p53 expression and tumour-cell proliferation fraction determined by MIB-1 count, p53 exon 5 and 6 mutations and HER-2/neu oncogene amplification were detected by immunohistochemistry, PCR-SSCP and slot-blot hybridization, respectively. Increased MIB-1 count, p53 expression, HER-2/neu oncogene amplification and p53 mutations were detected in 33%, 29%, 10% and 8% of tumours, respectively. Statistically significant associations were observed between p53 expression or MIB-1 count and age below 50 years, high-grade tumours, medullary carcinomas, and absence of hormone receptors. p53 mutations were associated with increased MIB-1 count, HER-2/neu oncogene amplification and absence of hormone receptors, but not with age, tumour size or grade, histological subtype, or the number of axillary nodes involved. After a median follow-up of 66 months, p53 expression was observed to be associated with significant increases in risk of both relapse and death from breast cancer, but not after adjusting for the effect of other parameters. In these analyses, MIB-1 count, and not HER-2/neu oncogene amplification, was an independent predictor of prognosis. In node-negative patients, only p53 exon 5 and 6 mutations and MIB-1 count were associated with a statistically significant increase in risk of death from breast cancer, independent of tumour size and ER concentration. We conclude that tumour-cell proliferation fraction, as measured by MIB-1 count, is the most useful parameter of breast-cancer prognosis, with the exception of ER, tumour size and the number of axillary nodes involved.

Long term prognostic value of growth fraction determination by Ki-67 immunostaining in primary operable breast cancer

An immunohistochemical determination of the growth fraction (GF) with the Ki-67 monoclonal antibody has been performed in a prospective series of 140 patients with primary operable breast carcinoma. GF ranged from 0% to 43% Ki-67 stained cells with a median value of 8%. High GF (> 8%) was significantly associated with axillary node involvement (p = 0.006), aneuploidy (p = 0.008), histologic grade (p = 0.03), and S-phase fraction > 5% determined by flow cytometry (p = 0.01). After a median follow-up of 6 years, the univariate analysis did not show significant correlation between high GF and worse relapse-free survival (p = 0.10) or shorter overall survival. However, a multivariate analysis on relapse-free survival, performed in 127 comparable patients, showed that GF was an independent predictive factor (p = 0.03) together with nodal status (p = 0.00001), age under 45 years (p = 0.0008), and chemotherapy (0.006). In node negative patients, GF was still an independent prognostic indicator (p = 0.002) together with age under 45 years (p = 0.0003). Tumor proliferative activity evaluated by the monoclonal antibody Ki-67 appears to be an effective indicator of prognosis in breast cancer and could be of assistance in the decision making of adjuvant therapy in node negative patients.