Lila Zabaglo

Prognostic Value of a Combined Estrogen Receptor, Progesterone Receptor, Ki-67, and Human Epidermal Growth Factor Receptor 2 Immunohistochemical Score and Comparison With the Genomic Health Recurrence Score in Early Breast Cancer

PURPOSE We recently reported that the mRNA-based, 21-gene Genomic Health recurrence score (GHI-RS) provided additional prognostic information regarding distant recurrence beyond that obtained from classical clinicopathologic factors (age, nodal status, tumor size, grade, endocrine treatment) in women with early breast cancer, confirming earlier reports. The aim of this article is to determine how much of this information is contained in standard immunohistochemical (IHC) markers. PATIENTS AND METHODS The primary cohort comprised 1,125 estrogen receptor-positive (ER-positive) patients from the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial who did not receive adjuvant chemotherapy, had the GHI-RS computed, and had adequate tissue for the four IHC measurements: ER, progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2), and Ki-67. Distant recurrence was the primary end point, and proportional hazards models were used with sample splitting to control for overfitting. A prognostic model that used classical variables and the four IHC markers (IHC4 score) was created and assessed in a separate cohort of 786 patients. RESULTS All four IHC markers provided independent prognostic information in the presence of classical variables. In sample-splitting analyses, the information in the IHC4 score was found to be similar to that in the GHI-RS, and little additional prognostic value was seen in the combined use of both scores. The prognostic value of the IHC4 score was further validated in the second separate cohort. CONCLUSION This study suggests that the amount of prognostic information contained in four widely performed IHC assays is similar to that in the GHI-RS. Additional studies are needed to determine the general applicability of the IHC4 score.

An International Ki67 Reproducibility Study

BACKGROUND In breast cancer, immunohistochemical assessment of proliferation using the marker Ki67 has potential use in both research and clinical management. However, lack of consistency across laboratories has limited Ki67s value. A working group was assembled to devise a strategy to harmonize Ki67 analysis and increase scoring concordance. Toward that goal, we conducted a Ki67 reproducibility study. METHODS Eight laboratories received 100 breast cancer cases arranged into 1-mm core tissue microarrays-one set stained by the participating laboratory and one set stained by the central laboratory, both using antibody MIB-1. Each laboratory scored Ki67 as percentage of positively stained invasive tumor cells using its own method. Six laboratories repeated scoring of 50 locally stained cases on 3 different days. Sources of variation were analyzed using random effects models with log2-transformed measurements. Reproducibility was quantified by intraclass correlation coefficient (ICC), and the approximate two-sided 95% confidence intervals (CIs) for the true intraclass correlation coefficients in these experiments were provided. RESULTS Intralaboratory reproducibility was high (ICC = 0.94; 95% CI = 0.93 to 0.97). Interlaboratory reproducibility was only moderate (central staining: ICC = 0.71, 95% CI = 0.47 to 0.78; local staining: ICC = 0.59, 95% CI = 0.37 to 0.68). Geometric mean of Ki67 values for each laboratory across the 100 cases ranged 7.1% to 23.9% with central staining and 6.1% to 30.1% with local staining. Factors contributing to interlaboratory discordance included tumor region selection, counting method, and subjective assessment of staining positivity. Formal counting methods gave more consistent results than visual estimation. CONCLUSIONS Substantial variability in Ki67 scoring was observed among some of the worlds most experienced laboratories. Ki67 values and cutoffs for clinical decision-making cannot be transferred between laboratories without standardizing scoring methodology because analytical validity is limited.

Detection of circulating epithelial cells in the blood of patients with breast cancer: comparison of three techniques

This study compares the sensitivities and specificities of three techniques for the detection of circulating epithelial cells in the blood of patients with breast cancer. The number of circulating epithelial cells present in the blood of 40 patients with metastatic breast cancer and 20 healthy volunteers was determined by: immunomagnetic separation (IMS) and laser scanning cytometry (LSC), cell filtration and LSC and a multimarker real-time RT–PCR assay. Numbers of cytokeratin-positive cells identified and expression of three PCR markers were significantly higher in the blood of patients with breast cancer than in healthy volunteers. Using the upper 95% confidence interval of cells detected in controls to determine positive patient samples: 30% of patients with metastatic breast cancer were positive following cell filtration, 48% following IMS, and 60, 45 and 35% using real-time RT–PCR for cytokeratin 19, mammaglobin and prolactin-inducible peptide. Samples were significantly more likely to be positive for at least one PCR marker than by cell filtration (83 vs 30%, P<0.001) or IMS (83 vs 48%, P<0.001). The use of a multimarker real-time RT–PCR assay was therefore found to be the most sensitive technique for the detection of circulating epithelial cells in the blood of patients with breast cancer.

Factors Predicting Late Recurrence for Estrogen Receptor–Positive Breast Cancer

Background Adjuvant endocrine therapy beyond 5 years reduces recurrence in patients with estrogen receptor–positive breast cancer. We have previously shown that immunohistochemical markers (IHC4) and two gene expression profile tests (recurrence score [RS] and PAM50 risk of recurrence [ROR]) are associated with time to distant recurrence, and we have now assessed the value of each of these scores and routine clinical variables for predicting outcome, specifically in years 5 to 10. Methods We used univariate and multivariable proportional hazards models to determine the prognostic value of all variables and scores (IHC4, RS, ROR) for distant recurrence, separately in years 0 to 5 and specifically for years 5 to 10 for all patients. All statistical tests were two-sided. Results Nodal status and tumor size were at least as strong in years 5 to 10 as in years 0 to 5 (nodal status, years 5–10: χ2 = 21.72 vs years 0–5: χ2 = 11.08, both P < .001; tumor size, years 5–10: χ2 = 10.52 vs years 0–5: χ2 = 10.82, both P = .001). Ki67 and the overall IHC4 score were the only statistically significant biomarkers related to distant recurrence univariablely in the 5 to 10 year period (χ2 = 8.67, χ2 = 13.22, respectively). The ROR score was the strongest molecular prognostic factor in the late follow-up period (χ2 = 16.29; P < .001), whereas IHC4 (χ2 = 7.41) and RS (χ2 = 5.55) were only weakly prognostic in this period. Similar results were seen for all subgroups and for all recurrences. Conclusions None of the IHC4 markers provided statistically significant prognostic information in years 5 to 10, except for nodal status and tumor size. ROR gave the strongest prognostic information in years 5 to 10. These results may help select patients who could benefit most from hormonal therapy beyond 5 years of treatment.

An international study to increase concordance in Ki67 scoring

Although an important biomarker in breast cancer, Ki67 lacks scoring standardization, which has limited its clinical use. Our previous study found variability when laboratories used their own scoring methods on centrally stained tissue microarray slides. In this current study, 16 laboratories from eight countries calibrated to a specific Ki67 scoring method and then scored 50 centrally MIB-1 stained tissue microarray cases. Simple instructions prescribed scoring pattern and staining thresholds for determination of the percentage of stained tumor cells. To calibrate, laboratories scored 18 ‘training’ and ‘test’ web-based images. Software tracked object selection and scoring. Success for the calibration was prespecified as Root Mean Square Error of scores compared with reference <0.6 and Maximum Absolute Deviation from reference <1.0 (log2-transformed data). Prespecified success criteria for tissue microarray scoring required intraclass correlation significantly >0.70 but aiming for observed intraclass correlation ≥0.90. Laboratory performance showed non-significant but promising trends of improvement through the calibration exercise (mean Root Mean Square Error decreased from 0.6 to 0.4, Maximum Absolute Deviation from 1.6 to 0.9; paired t-test: P=0.07 for Root Mean Square Error, 0.06 for Maximum Absolute Deviation). For tissue microarray scoring, the intraclass correlation estimate was 0.94 (95% credible interval: 0.90–0.97), markedly and significantly >0.70, the prespecified minimum target for success. Some discrepancies persisted, including around clinically relevant cutoffs. After calibrating to a common scoring method via a web-based tool, laboratories can achieve high inter-laboratory reproducibility in Ki67 scoring on centrally stained tissue microarray slides. Although these data are potentially encouraging, suggesting that it may be possible to standardize scoring of Ki67 among pathology laboratories, clinically important discrepancies persist. Before this biomarker could be recommended for clinical use, future research will need to extend this approach to biopsies and whole sections, account for staining variability, and link to outcomes.

Cell filtration-laser scanning cytometry for the characterisation of circulating breast cancer cells

Epithelial cells may be detected in the circulation of the majority of patients with metastatic breast cancer. Quantification of such presumptive cancer cells might allow for the monitoring of patients with early or late stage disease as an early index of relapse. Additionally, biomarker analysis may allow a more rational approach to therapeutics. We have developed a new method for the detection and characterisation of these cells.

Assessment of the contribution of the IHC4+C score to decision making in clinical practice in early breast cancer

Background:The immunohistochemical (IHC) 4+C score is a cost-effective prognostic tool that uses clinicopathologic factors and four standard IHC assays: oestrogen receptor (ER), PR, HER2 and Ki67. We assessed its utility in personalising breast cancer treatment in a clinical practice setting, through comparison with Adjuvant! Online (AoL) and the Nottingham Prognostic Index (NPI).Methods:We prospectively gathered clinicopathologic data for postmenopausal patients with hormone receptor-positive, HER2-negative, N0-3 resected early breast cancer treated consecutively at our institution. We retrospectively calculated and compared prognostic scores. The primary endpoint was the proportion of patients reclassified from AoL-defined intermediate-risk by application of the IHC4+C score.Results:The median age of the 101 patients included in the analysis was 63. In all, 15 of the 26 patients classified as intermediate-risk by AoL were reallocated to a low-risk group by application of the IHC4+C score and no patient was reclassified as high-risk group. Of the 59 patients classified as intermediate-risk group by the NPI, 24 were reallocated to a low-risk group and 13 to a high-risk group.Conclusion:IHC4+C reclassifies more than half of the patients stratified as being in intermediate-risk group by the AoL and NPI. The use of IHC4+C may substantially improve decision-making on adjuvant chemotherapy.

Effects of cyclin D1 gene amplification and protein expression on time to recurrence in postmenopausal breast cancer patients treated with anastrozole or tamoxifen: a TransATAC study.

IntroductionGene amplification of CCND1 is observed in a subgroup of breast cancers with poor prognosis, whereas overexpression of the protein cyclin D1 has been linked to both worse and better clinical outcome. CCND1 amplification and protein overexpression have also been associated with resistance to treatment with tamoxifen or even to a potentially detrimental effect of tamoxifen.MethodsTo clarify these challenging and partly contrasting treatment predictive and prognostic links for cyclin D1 we analysed a large cohort of postmenopausal breast cancer patients randomised to receive either adjuvant anastrozole or tamoxifen, as part of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial. The CCND1 amplification status and protein expression of cyclin D1 were assessed by chromogenic in situ hybridisation and immunohistochemistry, respectively, in 1,155 postmenopausal, oestrogen-receptor-positive breast cancer patients included in the TransATAC substudy.ResultsAmplification of CCND1 was observed in 8.7% of the tumours and was associated with increased risk of disease recurrence (hazard ratio = 1.61; 95% confidence interval, 1.08 to 2.41) after adjustment for other clinicopathological parameters. In contrast, nuclear expression of cyclin D1 protein was associated with decreased recurrence rate (hazard ratio = 0.6; 95% confidence interval, 0.39 to 0.92). The intensity of nuclear or cytoplasmic expression was not of prognostic value. There was no significant interaction between cyclin D1 status and treatment efficacy, ruling out any major detrimental effect of tamoxifen in CCND1-amplified postmenopausal breast cancer.ConclusionsIn summary, CCND1 amplification and low nuclear expression of cyclin D1 predicted poor clinical outcome in postmenopausal breast cancer patients treated with either anastrozole or tamoxifen.Trial RegistrationCurrent Controlled Trials ISRCTN18233230.

Comparative validation of the SP6 antibody to Ki67 in breast cancer

Aim To compare SP6 and MIB1 antibodies for Ki67 staining in breast cancer. Background Immunohistochemical detection of Ki67 has been widely used to assess the proliferative fraction in breast cancer. Ki67 is used prognostically and is the primary end-point for some presurgical trials. MIB1 has been the preferred antibody, but SP6 has become available, with apparently improved performance. The importance of Ki67 led us to systematically compare SP6 with MIB1. Methods Two sets of tissue microarrays were used. These were constructed from formalin-fixed paraffin-embedded breast cancers: (i) 177 cancers with data on response to an aromatase inhibitor for advanced disease (cohort 1); (ii) 200 mainly oestrogen-receptor-positive cancers without response data (cohort 2). Twenty-eight pairs of core-cut biopsies taken before and after aromatase inhibitor treatment were also assessed (cohort 3). Stained sections were examined either visually or by using an image analysis system (Ariol). Results There was a strong correlation between the two antibodies in all cohorts of samples scored visually (cohort 1: n=161, r=0.93, p<0.0001; cohort 2: n=194, r=0.84, p<0.0001; cohort 3: n=54, r=0.89, p<0.0001). Correlation between visual and Ariol scores was markedly better with the SP6 antibody (r=0.71 and r=0.88 for MIB1 and SP6, respectively). Ki67 related similarly with time-to-treatment failure with the two antibodies (cohort 1). Changes in Ki67 values with the two antibodies after 2 weeks of aromatase inhibitor treatment also correlated strongly. Conclusions SP6 and MIB1 provide highly comparable measures of Ki67 that predict progression of advanced disease similarly. SP6 is substantially better suited than MIB1 to image analysis.

Relationship between estrogen receptor, progesterone receptor, HER-2 and Ki67 expression and efficacy of aromatase inhibitors in advanced breast cancer

BACKGROUND Surprisingly few data are published on the relevance of even commonly used biomarkers of response to aromatase inhibitors (AIs) in advanced breast cancer. Here, we aim to determine the effectiveness of AIs in that setting according to quantitative levels of estrogen receptor (ER), progesterone receptor (PgR) and Ki67 or human epithelial growth factor receptor-2 (HER-2) status. PATIENTS AND METHODS ER, PgR, HER-2 and Ki67 protein expressions were centrally assessed in 177 archival formalin-fixed paraffin-embedded primary or locally recurrent breast tumours from women who subsequently received AI treatment of advanced disease. RESULTS Among ER-positive patients (n = 146), higher PgR, but not ER, levels were associated with increased time to AI treatment failure (TTF). Higher Ki67 staining was associated with decreased TTF. ER-positive/HER-2-positive patients showed a non-significant trend for decreased TTF compared with ER-positive/HER-2-negative patients. PgR level, but not Ki67, remained a significant predictor of TTF in multivariate analysis of ER-positive patients. CONCLUSIONS Higher PgR and Ki67 levels are significantly associated with increased and decreased TTF, respectively, in ER-positive patients receiving AI treatment of advanced disease. The higher proliferation seen in PgR-negative tumours does not explain the poorer clinical responsiveness of this subgroup.