Margaret Hills

Biomarker Changes During Neoadjuvant Anastrozole, Tamoxifen, or the Combination: Influence of Hormonal Status and HER-2 in Breast Cancer—A Study from the IMPACT Trialists

PURPOSE To investigate the relationships between biomarker changes in breast cancer during neoadjuvant (preoperative) endocrine therapy. PATIENTS AND METHODS The IMPACT trial compared the preoperative use of tamoxifen with anastrozole alone or in combination in postmenopausal women (n = 330) with primary breast cancer. Biomarkers were measured in tumor biopsy specimens taken at baseline, and after 2 and 12 weeks of treatment. RESULTS 52 (93%) of 56, 46 (85%) of 54, and 37 (84%) of 44 patients in the anastrozole, tamoxifen, and combination groups, respectively. There was a significantly greater suppression of Ki67 in the anastrozole-treated group than in the tamoxifen- or combination-treated groups, which is parallel to the greater efficacy seen for anastrozole over these two treatments in the Arimidex, Tamoxifen, Alone or in Combination adjuvant trial. A positive relationship was noted between estrogen-receptor level and Ki67 suppression in all patients. Ki67 was reduced to a greater extent in progesterone receptor-positive tumors compared with progesterone receptor-negative tumors. HER-2-negative tumors tended to show a greater reduction in Ki67 compared with HER-2-positive tumors, but the difference was only significant in the tamoxifen group after 2 weeks, and in the anastrozole group after 12 weeks. CONCLUSION These results confirm the value of Ki67 as a molecular marker, and provide information regarding the relationships between treatment-induced changes in Ki67 and other important biomarkers. Studies such as this should help integrate agents targeted at growth factor signaling with endocrine agents in breast cancer.

A Marker of Homologous Recombination Predicts Pathologic Complete Response to Neoadjuvant Chemotherapy in Primary Breast Cancer

Purpose: To assess the prevalence of defective homologous recombination (HR)-based DNA repair in sporadic primary breast cancers, examine the clincopathologic features that correlate with defective HR and the relationship with neoadjuvant chemotherapy response. Experimental Design: We examined a cohort of 68 patients with sporadic primary breast cancer who received neoadjuvant anthracylcine-based chemotherapy, with core biopsies taken 24 hours after the first cycle of chemotherapy. We assessed RAD51 focus formation, a marker of HR competence, by immunofluorescence in postchemotherapy biopsies along with geminin as a marker of proliferative cells. We assessed the RAD51 score as the proportion of proliferative cells with RAD51 foci. Results: A low RAD51 score was present in 26% of cases (15/57, 95% CI: 15%–40%). Low RAD51 score correlated with high histologic grade (P = 0.031) and high baseline Ki67 (P = 0.005). Low RAD51 score was more frequent in triple-negative breast cancers than in ER- and/or HER2-positive breast cancer (67% vs. 19% respectively; P = 0.0036). Low RAD51 score was strongly predictive of pathologic complete response (pathCR) to chemotherapy, with 33% low RAD51 score cancers achieving pathCR compared with 3% of other cancers (P = 0.011). Conclusions: Our results suggest that defective HR, as indicated by low RAD51 score, may be one of the factors that underlie sensitivity to anthracycline-based chemotherapy. Defective HR is frequent in triple-negative breast cancer, but it is also present in a subset of other subtypes, identifying breast cancers that may benefit from therapies that target defective HR such as PARP inhibitors. Clin Cancer Res; 16(24); 6159–68. ©2010 AACR.

Extreme loss of immunoreactive p-Akt and p-Erk1/2 during routine fixation of primary breast cancer

IntroductionVery few studies have investigated whether the time elapsed between surgical resection and tissue fixation or the difference between core-cut and excision biopsies impact on immunohistochemically measured biomarkers, including phosphorylated proteins in primary breast cancer. The aim of this study was to characterise the differences in immunoreactivity of common biomarkers that may occur (1) as a result of tissue handling at surgery and (2) between core-cuts and resected tumours.MethodsCore-cuts taken from surgical breast cancer specimens immediately after resection (sample A) and after routine X-ray of the excised tumour (sample B) were formalin-fixed and paraffin-embedded and compared with the routinely fixed resection specimen (sample C). The variation in immunohistochemical expression of Ki67, oestrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor 2 (HER2), p-Akt and p-Erk1/2 were investigated.ResultsTwenty-one tissue sets with adequate tumour were available. Median time between collection of core-cuts A and B was 30 minutes (range, 20 to 80 minutes). None of the markers showed significant differences between samples A and B. Similarly, Ki67, ER, PgR and HER2 did not differ significantly between core-cuts and main resection specimen, although there was a trend for lower resection values for ER (P = 0.06). However, p-Akt and p-Erk1/2 were markedly lower in resections than core-cuts (median, 27 versus 101 and 69 versus 193, respectively; both P < 0.0001 [two-sided]). This difference was significantly greater in mastectomy than in lumpectomy specimens for p-Erk1/2 (P = 0.01).ConclusionsThe delay in fixation in core-cuts taken after postoperative X-ray of resection specimens has no significant impact on expression of Ki67, ER, PgR, HER2, p-Akt or p-Erk1/2. However, extreme loss of phospho-staining can occur during routine fixation of resection specimens. These differences are likely attributable to suboptimal fixation and may have major repercussions for clinical research involving these markers.

Comparison of the Systemic and Intratumoral Effects of Tamoxifen and the Aromatase Inhibitor Vorozole in Postmenopausal Patients With Primary Breast Cancer

PURPOSE To determine biologic differences, if any, between presurgical endocrine treatment with an aromatase inhibitor (vorozole) and tamoxifen in patients with postmenopausal primary breast cancer. PATIENTS AND METHODS Randomization was to 12 weeks of 2.5 mg of vorozole per day or 20 mg of tamoxifen per day, both orally. Clinical response was assessed monthly together with serum sex hormone binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrogens (E1, E2, and E1S), lipids, insulin-like growth factor-1 (IGF-1), and bone metabolites (CrossLaps CTx). Tissue samples for Ki67, apoptotic index (AI), estrogen receptor, and progesterone receptor were collected at 0, 2, and 12 weeks. RESULTS Ki67 fell by 58% and 43% (means) at 2 weeks in the vorozole and tamoxifen patients, respectively (P =.13). In the vorozole group, the correlations of proportional changes in Ki67 at 2 weeks with tumor volume changes and clinical response at 12 weeks were not significant (P =.09) and marginally significant (P =.04), respectively. Serum lipids did not differ between groups. Serum levels of EI, E2, and E1S were suppressed markedly by vorozole, whereas levels of SHBG increased and LH and FSH fell significantly with tamoxifen. IGF-1 levels fell significantly with tamoxifen (P =.001) compared with the nonsignificant rise with vorozole. Twelve-week CTx values fell by 19% with tamoxifen (P =.006) and rose by 11% with vorozole (P =.15). CONCLUSION The correlation with vorozole of Ki67 with volume and clinical response supports this as an intermediate marker. The nonsignificant effects on bone and lipid metabolism by the aromatase inhibitor may be important to consider for adjuvant and potential prevention strategies.

Proliferation and Apoptosis as Markers of Benefit in Neoadjuvant Endocrine Therapy of Breast Cancer

The study of changes in proliferation as a marker of treatment benefit during presurgical endocrine treatment of breast cancer has become increasingly popular, particularly using the nuclear marker Ki67, and holds the potential for prioritizing new treatments for full clinical development. There are weakly significant relationships between Ki67 change and clinical response that differ according to data handling. In the neoadjuvant Immediate Preoperative Anastrozole, Tamoxifen, or Combined with Tamoxifen trial, suppression of Ki67 at both 2 and 12 weeks was greater with the aromatase inhibitor anastrozole than with either tamoxifen or the combination of anastrozole and tamoxifen. We report here that absolute values of Ki67 after 2 weeks were also significantly lower with anastrozole than with tamoxifen and the combination. This indicates that it may be possible to make such comparisons using surgical samples only. We argue that these changes in proliferation and concurrent changes in apoptosis may be expected to be more predictive of adjuvant benefit from endocrine therapy than clinical response.

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.

Microarray-based comparative genomic hybridisation of breast cancer patients receiving neoadjuvant chemotherapy

We analysed the molecular genetic profiles of breast cancer samples before and after neoadjuvant chemotherapy with combination doxorubicin and cyclophosphamide (AC). DNA was obtained from microdissected frozen breast core biopsies from 44 patients before chemotherapy. Additional samples were obtained before the second course of chemotherapy (D21) and after the completion of the treatment (surgical specimens) in 17 and 21 patients, respectively. Microarray-based comparative genome hybridisation was performed using a platform containing ∼5800 bacterial artificial chromosome clones (genome-wide resolution: 0.9 Mb). Analysis of the 44 pretreatment biopsies revealed that losses of 4p, 4q, 5q, 12q13.11–12q13.12, 17p11.2 and 17q11.2; and gains of 1p, 2p, 7q, 9p, 11q, 19p and 19q were significantly associated with oestrogen receptor negativity. 16q21–q22.1 losses were associated with lobular and 8q24 gains with ductal types. Losses of 5q33.3–q4 and 18p11.31 and gains of 6p25.1–p25.2 and Xp11.4 were associated with HER2 amplification. No correlations between DNA copy number changes and clinical response to AC were found. Microarray-based comparative genome hybridisation analysis of matched pretreatment and D21 biopsies failed to identify statistically significant differences, whereas a comparison between matched pretreatment and surgical samples revealed a statistically significant acquired copy number gain on 11p15.2–11p15.5. The modest chemotherapy-driven genomic changes, despite profound loss of cell numbers, suggest that there is little therapeutic selection of resistant non-modal cell lineages.

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.

Time-related effects of estrogen withdrawal on proliferation- and cell death-related events in MCF-7 xenografts.

Endocrine treatments for human breast cancer have been based largely upon the removal of estrogenic stimuli. The regression of tumors after estrogen deprivation has generally been characterized as being due to reduced proliferation but more recently has been recognized to also involve increased apoptosis. The aim of our experiments was to define the associated changes in certain proliferation‐ and cell death‐related biological parameters after hormone withdrawal from estrogen‐dependent MCF‐7 xenografts in athymic nude mice using immunohistochemical techniques. The baseline estrogen receptor (ER) level of this MCF‐7 xenograft was relatively low (average H score 23) but it was strongly Bcl‐2‐, PgR‐ and pS2‐positive, indicating the functional integrity of estrogen signaling. Changes in proliferation (Ki‐67), apoptosis, ER, progesterone receptor (PgR), cyclin D1, p27kip1, Bcl‐2 and Bax expression were assessed during the 2 weeks after estrogen deprivation. ER levels rose markedly after estrogen ablation, whereas PgR levels fell to about 10% of baseline and pS2 levels halved. The proportion of Ki‐67‐positive cells was unchanged after 24 hr but by day 14 had reduced by about 80%. The normal levels of cyclin D1 also reduced after estrogen withdrawal in contrast to the rapid increase in levels of cyclin‐dependent kinase inhibitor p27kip1. This latter increase appeared to occur in advance of the changes in Ki‐67. The proportion of apoptotic cells increased from a mean 1.5% at baseline to 2.9% after 3 days and 4.7% after 14 days. There were reductions in both Bcl‐2 and Bax staining but these appeared to be greater for Bcl‐2, effectively decreasing the Bcl‐2/Bax ratio. Our results provide a framework for the use of these parameters as intermediate markers in comparisons of hormonal agents for human breast cancer treatment. Int. J. Cancer 81:309–313, 1999.

Residual Proliferative Cancer Burden to predict long-term outcome following neoadjuvant chemotherapy

BACKGROUND The purpose of this study was (i) to test the hypothesis that combining Ki67 with residual cancer burden (RCB) following neoadjuvant chemotherapy, as the residual proliferative cancer burden (RPCB), provides significantly more prognostic information than either alone; (ii) to determine whether also integrating information on ER and grade improves prognostic power. PATIENTS AND METHODS A total of 220 patients treated with neoadjuvant chemotherapy for primary breast cancer were included in the study. Analyses employed a Cox proportional hazard model. Prognostic indices (PIs) were created adding in Ki67, grade and ER to RCB. Leave-one-out cross-validation was used to reduce bias. The overall change in χ2 of the best model for each index was used to compare the prognostic ability of the different indices. RESULTS All PIs provided significant prognostic information for patients with residual disease following neoadjuvant chemotherapy. RPCB (χ2 = 61.4) was significantly more prognostic than either RCB (χ2 = 38.1) or Ki67 (χ2 = 53.8) alone P < 0.001. A PI incorporating RCB, Ki67 grade and ER provided the most prognostic information overall and gave χ2 = 73.8. CONCLUSIONS This study provides proof of principle that the addition of post-treatment Ki67 to RCB improves the prediction of long-term outcome. Prediction may be further improved by addition of post-treatment grade and ER and warrants further investigation for estimating post-neoadjuvant risk of recurrence. These indices may have utility in stratifying patients for novel therapeutic interventions after neoadjuvant chemotherapy.BACKGROUND The purpose of this study was (i) to test the hypothesis that combining Ki67 with residual cancer burden (RCB) following neoadjuvant chemotherapy, as the residual proliferative cancer burden (RPCB), provides significantly more prognostic information than either alone; (ii) to determine whether also integrating information on ER and grade improves prognostic power. PATIENTS AND METHODS A total of 220 patients treated with neoadjuvant chemotherapy for primary breast cancer were included in the study. Analyses employed a Cox proportional hazard model. Prognostic indices (PIs) were created adding in Ki67, grade and ER to RCB. Leave-one-out cross-validation was used to reduce bias. The overall change in χ(2) of the best model for each index was used to compare the prognostic ability of the different indices. RESULTS All PIs provided significant prognostic information for patients with residual disease following neoadjuvant chemotherapy. RPCB (χ(2) = 61.4) was significantly more prognostic than either RCB (χ(2) = 38.1) or Ki67 (χ(2) = 53.8) alone P < 0.001. A PI incorporating RCB, Ki67 grade and ER provided the most prognostic information overall and gave χ(2) = 73.8. CONCLUSIONS This study provides proof of principle that the addition of post-treatment Ki67 to RCB improves the prediction of long-term outcome. Prediction may be further improved by addition of post-treatment grade and ER and warrants further investigation for estimating post-neoadjuvant risk of recurrence. These indices may have utility in stratifying patients for novel therapeutic interventions after neoadjuvant chemotherapy.