Interobserver concordance of Ki67 labeling index in breast cancer: Japan Breast Cancer Research Group Ki67 Ring Study

The standardized assessment of Ki67 labeling index (LI) is of clinical importance to identify patients with primary breast cancer who could benefit from chemotherapy. In this study, we evaluated the interobserver concordance of Ki67 LI assessment. Six surgical pathologists participated and all the slides were prepared from archival breast cancer tissues fixed in 10% buffered formalin for 24 h and stained with MIB‐1. Three independent studies were conducted. In the first study, 30 stained slides were assessed using two different methods: the scoring system, with a positive rate scored from 1 (0–9%) to 10 (90–100%) by visual estimate; and the counting method, with approximately 1000 cells counted in hot spots. In the second study, 20 tumors with Ki67 LI 5–25% were assessed, and in the third study, 15 printed photographs of stained slides were assessed to avoid variations by selecting different fields. In study 1, the counting system (intraclass correlation coefficient [ICC], 0.66 [95% confidence interval 0.52–0.78]) demonstrated a better correlation than the scoring system (ICC, 0.57 [0.42–0.72]). In study 2, the assessment for Ki67 LI of 5–25% demonstrated a correlation (ICC, 0.68 [0.50–0.81]) similar to that of study 1 (unrestricted range of Ki67 LI). In study 3, the assessment of Ki67 LI by counting yielded a good concordance (ICC, 0.94 [0.88–0.97]). In conclusion, there was better concordance with the counting system, and concordance was high when the assessed field was predetermined, indicating that the selection of the evaluation area is critical for obtaining reproducible Ki67 LI in breast cancer.     

Ki67在乳腺癌中的表达水平及其对新辅助化疗患者预后的评估价值

目的研究Ki67表达水平对乳腺癌新辅助化疗后患者预后的评估价值。方法调取行乳腺癌新辅助化疗的120例患者的临床资料,并对其临床病理指标、Ki67的表达及预后进行回顾性分析。结果乳腺癌患者的病理有效率与月经状态、病理组织学类型、雌激素受体状态无关,与原发肿瘤大小、淋巴结转移情况有关(P<0.01)。新辅助化疗后患者的Ki67阳性表达率与化疗前相比显著降低(P<0.01);在病理有效率方面,化疗前Ki67高表达组经新辅助化疗后有效率明显高于Ki67低表达组,差异具有统计学意义(χ~2=19.00,P<0.01);Ki67表达化疗前后明显下降组的病理有效率明显高于轻度下降组病理有效率,差异具有统计学意义(χ~2=89.68,P<0.01)。结论 Ki67呈高表达状态时提示乳腺癌患者新辅助化疗效果良好,同时其表达变化也可对患者的病情进行有效的评估。     

Prognostic Significance of the Ki67 Scoring Categories in Breast Cancer Subgroups

BackgroundImmunohistochemical (IHC) expression of Ki67 has a prognostic and predictive value for breast cancer, and the IHC Ki67 labeling index is estimated by counting the number of positive and negative cells. It has not been clarified whether IHC Ki67 estimated using a semiquantitative scoring system has a prognostic value. We aimed to estimate the usefulness of scoring categories of IHC Ki67 as a prognostic factor for breast cancer subgroups.Patients and MethodsWe retrospectively identified patients in the Tokai University breast cancer database for whom IHC Ki67 data were available between January 1, 2000 and December 31, 2010. Survival curves were calculated using the Kaplan-Meier method and compared using the log-rank test.ResultsOf the 1331 primary breast cancer patients included in the study, In patients with estrogen receptor (ER)-positive and HER2-negative tumors (n = 971), high and intermediate Ki67 scores were associated with poorer relapse-free survival than low Ki67 scores (P < .001 and P = .002, respectively). Furthermore, in the multivariate analyses of this subgroup, progression-free survival (PFS) was significantly longer in patients with low Ki67 scores than in patients with high Ki67 scores (hazard ratio, 0.387; 95% confidence interval, 0.233-0.643; P < .001). In the multivariate analyses, the Ki67 score was not significantly associated with PFS in the ER-positive and HER2-positive, ER-negative and HER2-positive, or ER-negative and HER2-negative subgroups.ConclusionOur data demonstrated that low, intermediate, and high Ki67 scores have a prognostic value in breast cancer patients with ER-positive and HER2-negative tumors.     

Interlaboratory variability of Ki67 staining in breast cancer

BackgroundPostanalytic issues of Ki67 assessment in breast cancers like counting method standardisation and interrater bias have been subject of various studies, but little is known about analytic variability of Ki67 staining between pathology labs. Our aim was to study interlaboratory variability of Ki67 staining in breast cancer using tissue microarrays (TMAs) and central assessment to minimise preanalytic and postanalytic influences.MethodsThirty European pathology labs stained serial slides of a TMA set of breast cancer tissues with Ki67 according to their routine in-house protocol. The Ki67-labelling index (Ki67-LI) of 70 matched samples was centrally assessed by one observer who counted all cancer cells per sample. We then tested for differences between the labs in Ki67-LI medians by analysing variance on ranks and in proportions of tumours classified as luminal A after dichotomising oestrogen receptor–positive cancers into cancers showing low (<14%, luminal A) and high (≥14%, luminal B HER2 negative) Ki67-LI using Cochran's Q.ResultsSubstantial differences between the 30 labs were indicated for median Ki67-LI (0.65%–33.0%, p < 0.0001) and proportion of cancers classified as luminal A (17%–57%, p < 0.0001). The differences remained significant when labs using the same antibody (MIB-1, SP6, or 30-9) were analysed separately or labs without prior participation in external quality assurance programs were excluded (p < 0.0001, respectively).ConclusionSubstantial variability in Ki67 staining of breast cancer tissue was found between 30 routine pathology labs. Clinical use of the Ki67-LI for therapeutic decisions should be considered only fully aware of lab-specific reference values.     

Ki67在不同分子类型乳腺癌组织中的表达及意义

目的探讨Ki67在不同分子类型乳腺癌组织中的表达及临床意义。方法采用免疫组织化学法,检测368例乳腺癌组织标本中Ki67表达情况,采用Wilcoxon秩和检验分析Ki67在不同分子类型乳腺癌组织中的表达差异;采用Spearman秩相关方法,分析Ki67表达与原发肿瘤大小、腋窝淋巴结转移及病理分期等的相关性。结果 Lumina型、Her-2型及三阴型乳腺癌组织中Ki67表达强度无显著性差异(χ2=0.015,P=0.993);Ki67表达强度与Lumina型乳腺癌的原发肿瘤大小、腋窝淋巴结转移及病理分期呈正相关性(γs=0.167,P=0.013;γs=0.142,P=0.035;γs=0.165,P=0.014),而与Her-2型及三阴型乳腺癌的以上3个病理因素无显著性相关(P>0.05)。结论在Lumina型、Her-2型及三阴型乳腺癌组织中Ki67表达强度无显著性差异,Ki67表达强度与Lumina型乳腺癌的临床病理因素相关,是Lumina型乳腺癌的不良预后因素。     

Ki67 immunostaining in primary breast cancer: pathological and clinical associations

Ki67 immunostaining has been performed on 136 primary breast cancers and related to various clinical and pathological features of the disease. Staining was most frequently seen in poorly differentiated tumours showing high rates of mitotic activity, but was independent of tumour size, lymph-node status and ER expression. A high level of Ki67 immunostaining was often associated with early recurrence of breast cancer after mastectomy. These data are consistent with the concept of the Ki67 antibody detecting an antigen that is closely related to cell proliferation and thus provides a clinically useful marker for this important characteristic of the tumour.     

Reply to Ki67 in breast cancer: a useful prognostic marker!

The prognostic role of Ki67 in breast cancer patients remains unclear when we considered a normal population. Composition of population in clinical practice is sometimes different in comparison with population in the trial.     

Ki67: a time-varying biomarker of risk of breast cancer in atypical hyperplasia

Uncontrolled proliferation is a defining feature of the malignant phenotype. Ki67 is a marker for proliferating cells and is overexpressed in many breast cancers. Atypical hyperplasia is a premalignant lesion of the breast (relative risk ~ 4.0). Here, we asked if Ki67 expression could stratify risk in women with atypia. Ki67 expression was assessed immunohistochemically by digital image analysis in archival sections from 192 women with atypia diagnosed at the Mayo Clinic 1/1/67–12/31/91. Risk factor and follow-up data were obtained via study questionnaire and medical records. Observed breast cancer events were compared to population expected rates (Iowa SEER) using standardized incidence ratios (SIRs). We examined two endpoints: risk of breast cancer within 10 years and after 10 years of atypia biopsy. Thirty-two (16.7%) of the 192 women developed breast cancer over a median of 14.6 years. Thirty percent (58) of the atypias had ≥2% cells staining for Ki67. In these women, the risk of breast cancer within 10 years after atypia was increased (SIR 4.42 [2.21–8.84]) but not in those with <2% staining. Specifically, the cumulative incidence for breast cancer at 10 years was 14% in the high Ki67 vs. 3% in the low Ki67 group. Conversely, after 10 years, risk in the low Ki67 group rose significantly (SIR 5.69 [3.63–8.92]) vs. no further increased risk in the high Ki67 group (SIR 0.78 [0.11–5.55]). Ki67 appears to be a time-varying biomarker of risk of breast cancer in women with atypical hyperplasia.     

Prognostic significance of Ki67 index after neoadjuvant chemotherapy in breast cancer

Purpose

Recently, Ki67 index (cell proliferation marker) has been attracting a considerable attention as a prognostic factor in breast cancer but the prognostic significance of Ki67 after neoadjuvant chemotherapy (NAC) has rarely been examined.

Experimental design

Primary breast cancer patients (n = 102) treated with NAC (sequential paclitaxel 12 cycles (q1w) and 5-FU/epirubicin/cyclophosphamide 4 cycles (q3w)) were recruited in the study. Ki67, estrogen receptor (ER) and progesterone receptor (PR) and breast cancer resistant protein (BCRP) and P-glycoprotein were determined by immunohistochemistry and HER2 was determined by FISH in tumor tissues obtained before and after NAC, and their association with patient prognosis (relapse-free survival) was examined.

Results

Of the 102 patients, pCR was achieved in 30 (29.4%). In the 72 non-pCR patients, Ki67 index significantly (P < 0.001) decreased after NAC. Ki67 index after NAC, but not Ki67 index before NAC, was significantly associated with a patient prognosis (P = 0.022). Multivariate analysis has shown that Ki67 index after NAC is a marginally significant (P = 0.05) prognostic factor and that other biomarkers including ER, PR, BCRP, and P-glycoprotein before and after NAC are not significant.

Conclusions

Ki67 after NAC, but not before NAC, is prognostic in breast cancer patients, and might be clinically useful in the prognosis prediction of patients who do not achieve pCR after NAC. On the other hand, BCRP and P-glycoprotein before and after NAC are unlikely to be useful as prognostic factors in these patients.     

Ki67 Index in Breast Cancer: Correlation with Other Prognostic Markers and Potential in Pakistani Patients

Introduction: Breast cancer aggressiveness can be correlated with proliferation status of tumor cells, whichcan be ascertained with tumor grade and Ki67 indexing. However due to lack of reproducibility, the ASCO donot recommend routine use of Ki67 in determining prognosis in newly diagnosed breast cancers. We thereforeaimed to determine associations of the Ki67 index with other prognostic markers like tumor size, grade, lymphnode metastasis, ER, PR and HER2neu status. Methods: A total of 194 cases of newly diagnosed breast cancerwere included in the study. Immunohistochemical staining for ER, PR, HER2neu and Ki67 was performed bythe DAKO envision method. Associations of the Ki67 index with other prognostic factors were evaluated bothas continuous and categorical variables. Results: Mean age of the patients was 51.7 years (24-90). Mean Ki67index was 26.9% (1-90). ER, PR, HER2neu positivity was noted in 90/194 cases (46.4%), 74/194 cases (38.1%)and 110/194 cases (56.70%) respectively. Significant association was found between Ki67 and tumor grade,PR, HER2neu positivity and lymph node status, but no link was apparent with ER positivity and tumor size.There wasan inverse relation between Ki67 index and PR positivity, whereas a direct correlation was seen withHER2neu positivity. However, high Ki67 (>30%) was associated with decreased HER2neu positivity as comparedto intermediate Ki67 (16-30%). The same trend was established with lymph node metastasis. Conclusion: Ourstudy indicates that with high grade tumors, clinical utility of ki67 is greater in combination with other prognosticmarkers because we found that tumors with Ki67 higher than 30% have better prognostic profile comparedto tumors with intermediate Ki67 level, as reflected by slightly lower frequency of lymph node metastasis andHER2neu expression. Therefore we suggest that Ki67 index should be categorized into high, intermediate andlow groups when considering adjuvant chemotherapy and prognostic stratification.     

Quality indicators in breast cancer care: An update from the EUSOMA working group

In 2010, EUSOMA published a position paper, describing a set of benchmark quality indicators (QIs) that could be adopted by breast centres to allow standardised auditing and quality assurance and to establish an agreed minimum standard of care. Towards the end of 2014, EUSOMA decided to update the paper on QIs to consider and incorporate new scientific knowledge in the field. Several new QIs have been included to address the need for improved follow-up care of patients following primary treatments. With regard to the management of elderly patients, considering the complexity, the expert group decided that, for some specific quality indicators, if centres fail to meet the minimum standard, older patients will be excluded from analysis, provided that reasons for non-adherence to the QI are specified in the clinical chart and are identified at the review of the clinical records. In this way, high standards are promoted, but centres are able to identify and account for the effect of non-standard treatment in the elderly. In the paper, there is no QI for outcome measurements, such as relapse rate or overall survival. However, it is hoped that this will be developed in time as the databases mature and user experience increases. All breast centres are required to record outcome data as accurately and comprehensively as possible to allow this to occur. In the paper, different initiatives undertaken at international and national level to audit quality of care through a set of QIs have been mentioned.     

Correlation between Ki67 and Histological Grade in Breast Cancer Patients Treated with Preoperative Chemotherapy

Background and Aim: Breast cancer (BC) is a heterogeneous disease and cell proliferation markers may helpto identify subtypes of clinical interest. We here analyzed the correlation between cell proliferation determinedby Ki67 and HG in BC patients undergoing preoperative chemotherapy (PCT). Materials and Methods: Weobtained clinical/pathological data from patients with invasive BC treated at our institution from 1999 until2012. Expression of estrogen receptor (ER), progesterone receptor (PR), epidermal growth factor receptor type2 (HER2) and Ki67 were determined by immuno-histochemistry (IHC). Clinicopathological subtypes weredefined as: Luminal A, ER and/or PR positive, HER2 negative, HG 1 or 2; Luminal B, ER and/or PR positive,HER2 negative or positive and/or HG 3; triple negative (TN), ER, PR and HER2 negative independent ofHG; HER2 positive, ER, PR negative and HER2 positive, independent of HG. By using Ki67, a value of 14%separated Luminal A and B tumors, independently of the histological grade. We analyzed correlations betweenKi67 and HG, to define BC subtypes and their predictive value for response to PCT. Results: 1,560 BC patientswere treated in the period, 147 receiving PCT (9.5%). Some 57 had sufficient clinicopathological information tobe included in the study. Median age was 52 years (26-72), with 87.7% invasive ductal carcinomas (n=50). Weperformed IHC for Ki67 in 40 core biopsies and 50 surgical biopsies, 37 paired samples with Ki67 before andafter chemotherapy being available. There was no significant correlation between Ki67 and HG (p=0.237), bothcategorizing patients into different subtypes. In most cases Ki67 decreased after PCT (65.8%). Only 3 patientshad pathologic complete response (cPR). Conclusions: In our experience we did not find associations betweenKi67 and HG. Determination of clinicopathological luminal subtypes differs by using Ki67 or HG.     

胸苷激酶1和Ki67在乳腺癌中的表达及其对预后的价值

目的探讨胸苷激酶1（TKl）、Ki67单独表达及联合表达对乳腺癌复发转移的影响。方法选取广州医学院第二附属医院乳腺外科2005年3月至2007年6月问手术切除的乳腺癌患者组织标本65例,均经病理证实。分为A、B两组,A组37例,为乳腺癌在5年内出现复发或转移者,B组28例,为无瘤生存超过5年者。分别测量A、B两组TK1及Ki67表达情况并描述生存曲线。结果TKlA组阳性率为91．8％,B组阳性率67．8％（x2=6．116,P=0．013）,Ki67A组阳性率为78．4％,B组阳性率42．9％（X2=8．635,P=0．003）。A、B两组TKl和Ki67均呈阳性表达的比率分别为67．6％和39．3％（x2=5．159,P=0．023）。经Kaplan．Meier法生存曲线证实,与TK1和Ki67单独阳性表达者相比,联合阳性表达者的无瘤生存率显著降低,差异有统计学意义（x2=6．137,P=0．046）。结论TK1、Ki67均阳性表达是乳腺癌复发转移的高危因素,其预后较两者单独阳性表达者更差。     

激素受体阴性乳腺癌Ki67表达与新辅助化疗疗效的关系

摘 要：［目的］ 探讨激素受体阴性乳腺癌Ki67表达与新辅助化疗疗效的关系。［方法］ 收集2006年1月5日至2015年12月31日在兰州大学第二医院手术治疗的75例符合条件的HR阴性乳腺癌患者,根据免疫组化法检测的Ki67表达水平将其分为高表达组（>30%）、中表达组（14%~30%）、低表达组（<14%）。回顾性分析三组患者的临床病理特征,分析 Ki67不同表达水平与新辅助化疗疗效之间的关系。［结果］ 4周期新辅助化疗后RR为85.3%（64/75）,其中CR为29.3%（22/75）,PR为56.0%（42/75）,SD为14.7%（11/75）,无PD病例。其中pCR仅占17.3%（13/75）。Ki67高表达组与绝经前状态、较大的肿瘤直径、高肿瘤分级、淋巴管浸润、淋巴结阳性、HR阴性以及HER2阳性相关（P<0.05）。新辅助化疗可显著性降低Ki67的阳性表达率(P<0.01）。Logistic回归显示Ki67是乳腺癌新辅助化疗效果的独立预测因素（P>0.05）。［结论］ Ki67表达水平及其变化可预测HR阴性乳腺癌肿瘤新辅助化疗疗效。     

p53突变型乳腺癌中Ki67表达水平的临床意义

目的：探讨乳腺癌组织中p53的突变情况及Ki67的表达水平,明确p53与Ki67联合作用在乳腺癌临床病理因素上的体现。方法：应用免疫组化SP法检测165例乳腺癌组织中p53、Ki67的表达,分析其与临床病理因素之间的关系。结果：p53的突变率为55.8%（92/165）,Ki67的阳性表达率为69.1% （114/165）。p53的突变情况与患者年龄、肿块大小、淋巴结转移、TNM分期、ER和PR的表达水平无关,但与HER-2的表达水平呈正相关。在总人群中Ki67的表达水平与肿块大小和淋巴结转移无关。亚组分析显示在p53突变的患者中,Ki67的表达水平与肿块的大小呈正相关（r=0.311,P=0.003）,与淋巴结转移呈正相关（r=0.342,P=0.001）。结论：在p53突变型乳腺癌中Ki67的表达与T分期及N分期均呈正相关,在p53突变人群中Ki67对乳腺癌的生物学行为和患者的预后可能有更高的预测价值,二者联合检测与解读可能更有助于判断乳腺癌患者的预后。