ICON: a randomized phase IIb study evaluating immunogenic chemotherapy combined with ipilimumab and nivolumab in patients with metastatic hormone receptor positive breast cancer.

BACKGROUND: Immunotherapy with checkpoint inhibitors (CPI) targeting PD-1 or CTLA-4 has emerged as an important treatment modality for several cancer forms. In hormone receptor positive breast cancer (HR + BC), this therapeutic approach is largely unexplored. We have started a clinical trial, ICON (CA209-9FN), evaluating CPI combined with selected chemotherapy in patients with metastatic HR + BC. The tumor lymphocyte infiltration is predictive for the effect of chemotherapy in BC. In ICON, we use anthracycline, which are considered as "immunogenic" chemotherapy, and low-dose cyclophosphamide, which has been reported to counter immunosuppressive cells. METHODS: ICON is a randomized exploratory phase IIb study evaluating the safety and efficacy of combining nivolumab (nivo; anti-PD-1) and ipilimumab (ipi; anti-CTLA-4) with chemotherapy in subjects with metastatic HR + BC. Primary objectives are aassessment of toxicity and progression-free survival. The trial will enrol 75 evaluable subjects, randomized 2:3 into two arms (A:B). Patients in Arm A receive only chemotherapy, i.e. pegylated liposomal doxorubicin (PLD 20 mg/m2 intravenously every 2nd week) + cyclophosphamide (cyclo; 50 mg per day, first 2 weeks in each 4 week cycle). Patients in Arm B receive PLD + cyclo + ipilimumab (1 mg intravenously every 6th week) + nivolumab (240 mg intravenously every 2nd week). Patients in arm A will be offered ipi + nivo after disease progression. DISCUSSION: ICON is among the first clinical trials combining chemotherapy with PD-1 and CTLA-4 blockade, and the first in BC. There is a strong preclinical rationale for exploring if anthracyclines, which are considered to induce immunogenic cell death, synergize with CPI, and for combining PD-1 and CTLA-4 blockade, as these checkpoints are important in different phases of the immune response. If the ICON trial suggests acceptable safety and provide a signal of clinical efficacy, further studies are warranted. The cross-over patients from Arm A receiving ipilimumab/nivolumab without concomitant chemotherapy represent the first BC cohort receiving this therapy. The ICON trial includes a series of translational sub-projects addressing clinically important knowledge gaps. These studies may uncover biomarkers or mechanisms of efficacy and resistance, thereby informing the development of novel combinatory regimes and of personalised biomarker-based therapy. Trial registration NCT03409198, Jan 24th 2018; https://clinicaltrials.gov/ct2/show/record/NCT03409198.

ALICE: a randomized placebo-controlled phase II study evaluating atezolizumab combined with immunogenic chemotherapy in patients with metastatic triple-negative breast cancer.

BACKGROUND: Immunotherapy with checkpoint inhibitors (CI) represents an important novel development in cancer treatment. Metastatic triple-negative breast cancer (mTNBC) is incurable, with a median survival of only ~ 13 months. We have initiated the randomized placebo-controlled phase IIb study ALICE, evaluating PD-L1 blockade combined with immunogenic chemotherapy in mTNBC patients (n = 75). Intriguingly, the host immune response is strongly predictive for the effect of chemotherapy in mTNBC. In the ALICE trial, we release the brake on the immune response by use of atezolizumab, an inhibitory antibody against PD-L1. We utilize anthracyclines, shown to trigger the immune system, and low-dose cyclophosphamide, which has been reported to counter immunosuppressive cells. METHODS: ALICE is a randomized, double-blind, placebo-controlled exploratory phase II study evaluating the safety and efficacy of atezolizumab when combined with immunogenic chemotherapy in subjects with mTNBC. The trial will enroll 75 evaluable subjects, randomized 2:3 into two arms (A:B). The patients receive identical chemotherapy, i.e. pegylated liposomal doxorubicin (PLD 20 mg/m2 intravenously every 2nd week) + cyclophosphamide (50 mg per day, first 2 weeks in each 4 week cycle). Patients in arm A receive placebo, while patients in arm B receive atezolizumab. The primary objectives are assessment of toxicity and progression-free survival. The secondary objectives include overall survival, tumor response rate, clinical benefit rate, patient reported outcomes, biomarkers and assessment of tumor-immune evolution during therapy. DISCUSSION: The question of how CI should be combined with chemotherapy, is a key challenge facing the field. There is a strong preclinical rationale for exploring if anthracyclines, which are considered to induce immunogenic cell death, synergize with PD-L1 blockade, and if low-dose cyclophosphamide counters tumor tolerance. However, the data from patients is as yet very limited, and the clinical evaluation of these hypotheses is among the key objectives in the ALICE trial. The study includes extensive biobanking and translational sub-projects, also addressing other clinically important questions. These analyses may uncover mechanisms of drug efficacy or tumor resistance, and identify biomarkers allowing personalized therapy. If the trial suggests acceptable safety of the ALICE therapy and provide a signal of clinical efficacy, further studies are warranted. Trial registration NCT03164993, May 24th 2017; https://clinicaltrials.gov/ct2/show/record/NCT03164993.

The use of breast imaging for predicting response to neoadjuvant lapatinib, trastuzumab and their combination in HER2-positive breast cancer: Results from Neo-ALTTO.

AIM: To determine the value of mammography and breast ultrasound (US) in predicting outcomes in HER2 positive breast cancer patients (pts) within Neo-ALTTO trial. PATIENTS AND METHODS: Mammography and US were required at baseline, week 6 and surgery. Two independent blinded investigators reviewed the measurements and assigned the corresponding response category. Pts showing complete or partial response according to RECIST (v1.1) were classified as responders. The association between imaging response at week 6 or prior to surgery was evaluated with respect to pathological complete response (pCR) and event-free Survival (EFS). RESULTS: Of the 455 pts enrolled in the trial, 267 (61%) and 340 (77%) had evaluable mammography and US at week 6; 248 (56%) and 309 (70%) pts had evaluable mammography and US prior to surgery. At week 6, 32% and 43% of pts were classified as responders by mammography and US, respectively. pCR rates were twice as high for responders than non-responders (week 6: 46% versus 23% by US, p < 0.0001; 41% versus 24% by mammography, p = 0.007). Positive and negative predictive values of mammography and US prior to surgery were 37% and 35%, and 82% and 70%, respectively. No significant correlation was found between response by mammography and/or US at week 6/surgery and EFS. CONCLUSIONS: Mammography and US were underused in Neo-ALTTO although US had the potential to assess early response whereas mammography to detect residual disease prior to surgery. Our data still emphasise the need for further imaging studies on pts treated with neoadjuvant HER2-targeted therapy.

Safety of everolimus plus exemestane in patients with hormone-receptor-positive, HER2-negative locally advanced or metastatic breast cancer progressing on prior non-steroidal aromatase inhibitors: primary results of a phase IIIb, open-label, single-arm, expanded-access multicenter trial (BALLET).

BACKGROUND: This European phase IIIb, expanded-access multicenter trial evaluated the safety of EVE plus EXE in a patient population similar to BOLERO-2. PATIENTS AND METHODS: Post-menopausal women aged ≥18 years with hormone receptor-positive, human epidermal growth factor-receptor-2-negative advanced breast cancer (ABC) recurring/progressing during/after prior non-steroidal aromatase inhibitors were enrolled. The primary objective was safety of EVE plus EXE based on frequency of adverse events (AEs), and serious AEs (SAEs). The secondary objective was to evaluate AEs of grade 3/4 severity. RESULTS: The median treatment duration was 5.1 months [95% confidence interval (CI) 4.8-5.6] for EVE and 5.3 months (95% CI 4.8-5.6) for EXE. Overall, 2131 patients were included in the analysis; 81.8% of patients experienced EVE- or EXE-related or EVE/EXE-related AEs (investigator assessed); 27.2% were of grade 3/4 severity. The most frequently reported non-hematologic AEs were (overall %, % EVE-related) stomatitis (52.8%; 50.8%) and asthenia (22.8%; 14.6%). The most frequently reported hematologic AEs were (overall %, % EVE-related) anemia (14.4%; 8.1%) and thrombocytopenia (5.9%; 4.6%). AE-related treatment discontinuations were higher in elderly (≥70 years) versus non-elderly patients (23.8% versus 13.0%). The incidence of EVE-related AEs in both elderly and non-elderly patients appeared to be lower in first-line ABC versus later lines. The incidence of AEs (including stomatitis/pneumonitis) was independent of BMI status (post hoc analysis). Overall, 8.5% of patients experienced at least one EVE-related SAE. Of the 121 on-treatment deaths (5.7%), 66 (3.1%) deaths were due to disease progression and 46 (2.2%) due to AEs; 4 deaths were suspected to be EVE-related. CONCLUSIONS: This is the largest ever reported safety dataset on a general patient population presenting ABC treated with EVE plus EXE and included a sizeable elderly subset. Although the patients were more heavily pretreated, the safety profile of EVE plus EXE in BALLET was consistent with BOLERO-2. CLINICAL TRIAL REGISTRATION: EudraCT Number: 2012-000073-23.

Disseminated tumour cells in the bone marrow in early breast cancer: morphological categories of immunocytochemically positive cells have different impact on clinical outcome.

Detection of disseminated tumour cells (DTCs) in bone marrow by immunocytochemistry (ICC) includes morphological evaluation of cytokeratin immunopositive cells. The aim of this study was to disclose the prognostic significance of different morphological categories of ICC-positive cells according to treatment status and tumour subtype. Bone marrow samples (at surgery) were analysed for the presence of cytokeratin-positive DTCs by a standard immunocytochemical method. The immunopositive cells were classified into the following categories, prior to any analysis of the association between DTCs and clinical outcome: tumour cells (TC), uninterpretable cells (UIC), hematopoietic cells (HC), and questionable HC (QHC). The analysis included 747 early breast cancer patients. Median follow-up was 84 months for relapse, and 99 months for death. The categorisation of the ICC positive cells revealed TC in 13.3 % of the patients, whereas 13.1, 17.8, and 21.4 % of the cases were positive for UIC, QHC, and HC, respectively. Analysing all patients, only TC and UIC predicted systemic relapse. Separate analysis of all patients not receiving adjuvant systemic treatment (No-Adj; n = 389) showed that only QHC were associated with reduced survival (DDFS: p = 0.008; BCSS: p = 0.004, log rank) and the presence of QHC also remained significant in multivariate analysis. Primary tumour subgroup analysis (of all patients) by hormone receptors (HR) and HER2, demonstrated that only TC/UIC had prognostic impact in the HR+/HER2- patients, whereas presence of QHC was associated with unfavourable outcome only in triple negative patients (DDFS: p = 0.004; BCSS: p = 0.024). Patients with ≥3HC had improved outcome compared to those with fewer/no HC (DDFS: p = 0.005; BCSS: p = 0.009). Hence, morphological DTC subgroups may differ in clinical significance according to primary tumour subtype and treatment status. This emphasises the importance of DTC characterisation, and separate analyses of DTC categories according to tumour subtype. Hematopoietic ("false positive") cells might predict an immune-related favorable clinical outcome.

Neoadjuvant chemotherapy in breast cancer-response evaluation and prediction of response to treatment using dynamic contrast-enhanced and diffusion-weighted MR imaging.

OBJECTIVE: To explore the predictive value of MRI parameters and tumour characteristics before neoadjuvant chemotherapy (NAC) and to compare changes in tumour size and tumour apparent diffusion coefficient (ADC) during treatment, between patients who achieved pathological complete response (pCR) and those who did not. METHODS: Approval by the Regional Ethics Committee and written informed consent were obtained. Thirty-one patients with invasive breast carcinoma scheduled for NAC were enrolled (mean age, 50.7; range, 37-72). Study design included MRI before treatment (Tp0), after four cycles of NAC (Tp1) and before surgery (Tp2). Data in pCR versus non-pCR groups were compared and cut-off values for pCR prediction were evaluated. RESULTS: Before NAC, HER2 overexpression was the single significant predictor of pCR (p = 0.006). At Tp1 ADC, tumour size and changes in tumour size were all significantly different in the pCR and non-pCR groups. Using 1.42 × 10(-3) mm(2)/s as the cut-off value for ADC, pCR was predicted with sensitivity and specificity of 88% and 80%, respectively. Using a cut-off value of 83% for tumour volume reduction, sensitivity and specificity for pCR were 91% and 80%. CONCLUSION: ADC, tumour size and tumour size reduction at Tp1 were strong independent predictors of pCR.

Comparison of the Agilent, ROMA/NimbleGen and Illumina platforms for classification of copy number alterations in human breast tumors.

BACKGROUND: Microarray Comparative Genomic Hybridization (array CGH) provides a means to examine DNA copy number aberrations. Various platforms, brands and underlying technologies are available, facing the user with many choices regarding platform sensitivity and number, localization, and density distribution of probes. RESULTS: We evaluate three different platforms presenting different nature and arrangement of the probes: The Agilent Human Genome CGH Microarray 44 k, the ROMA/NimbleGen Representational Oligonucleotide Microarray 82 k, and the Illumina Human-1 Genotyping 109 k BeadChip, with Agilent being gene oriented, ROMA/NimbleGen being genome oriented, and Illumina being genotyping oriented. We investigated copy number changes in 20 human breast tumor samples representing different gene expression subclasses, using a suite of graphical and statistical methods designed to work across platforms. Despite substantial differences in the composition and spatial distribution of probes, the comparison revealed high overall concordance. Notably however, some short amplifications and deletions of potential biological importance were not detected by all platforms. Both correlation and cluster analysis indicate a somewhat higher similarity between ROMA/NimbleGen and Illumina than between Agilent and the other two platforms. The programs developed for the analysis are available from http://www.ifi.uio.no/bioinf/Projects/. CONCLUSION: We conclude that platforms based on different technology principles reveal similar aberration patterns, although we observed some unique amplification or deletion peaks at various locations, only detected by one of the platforms. The correct platform choice for a particular study is dependent on whether the appointed research intention is gene, genome, or genotype oriented.

Extracellular matrix signature identifies breast cancer subgroups with different clinical outcome.

Prediction of the clinical outcome of breast cancer is multi-faceted and challenging. There is growing evidence that the complexity of the tumour micro-environment, consisting of several cell types and a complex mixture of proteins, plays an important role in development, progression, and response to therapy. In the current study, we investigated whether invasive breast tumours can be classified on the basis of the expression of extracellular matrix (ECM) components and whether such classification is representative of different clinical outcomes. We first examined the matrix composition of 28 primary breast carcinomas by morphology and gene expression profiling using 22K oligonucleotide Agilent microarrays. Hierarchical clustering of the gene expression profile of 278 ECM-related genes derived from the literature divided the tumours into four main groups (ECM1-4). A set of selected differentially expressed genes was validated by immunohistochemistry. The robustness of the ECM classification was confirmed by studying the four ECM groups in a previously published gene expression data set of 114 early-stage primary breast carcinomas profiled using cDNA arrays. Univariate survival analysis showed significant differences in clinical outcome among the various ECM subclasses. One set of tumours, designated ECM4, had a favourable outcome and was defined by the overexpression of a set of protease inhibitors belonging to the serpin family, while tumours with an ECM1 signature had a poorer prognosis and showed high expression of integrins and metallopeptidases, and low expression of several laminin chains. Furthermore, we identified three surrogate markers of ECM1 tumours: MARCO, PUNC, and SPARC, whose expression levels were associated with breast cancer survival and risk of recurrence. Our findings suggest that primary breast tumours can be classified based upon ECM composition and that this classification provides relevant information on the biology of breast carcinomas, further supporting the hypothesis that clinical outcome is strongly related to stromal characteristics.

A European interlaboratory testing of three well-known procedures for immunocytochemical detection of epithelial cells in bone marrow. Results from analysis of normal bone marrow.

BACKGROUND: This investigation intended to study the unspecific background to be expected in normal bone marrow (BM), comparing three well recognized protocols for immunocytochemical detection of disseminated carcinoma cells. The interlaboratory variation in screening and evaluation of stained cells was analyzed and different screening methods were compared. METHODS: BM mononuclear cells (BM MNC) from 48 normal BMs were immunostained in parallel by three participating laboratories. The protocols, based on three different anti-cytokeratin antibodies, have all been in common use for detection of disseminated carcinoma cells: the A45-B/B3 protocol (Hamburg), the CK2 protocol (Augsburg) and the AE1AE3 protocol (Oslo). For all protocols, the immunostained cells were visualized by the same alkaline-phosphatase (AP) detection system (APAAP) followed by detection of the cells by manual screening and by two different automated screening systems (ACIS from Chromavision and MDS1 from Applied Imaging). Detected AP-visualized cells were morphologically classified into unambiguous hematopoietic (Uhc) and questionable cells (Qc, potentially interpreted as tumor cells). RESULTS: Seven of 48 BMs (15%) harbored > or = 1 AP-visualized cell(s) among 1 x 10(6) BM MNC, both for the A45-B/B3- and for the AE1AE3 protocol, while for CK2 a higher proportion of BMs (21 BMs; 44%) harbored AP-visualized cells (P < 0.01, McNemar's test). The number of Qc was, for all protocols, 1 log lower than the total number of AP-visualized cells. On average, the frequency of Qc was 0.04, 0.08, and 0.02 per 10(6) BM MNC with A45-B/B3, CK2 and AE1AE3, respectively, and the number of Qc-positive BMs 1, 4, and 1. The MDS1 screening sensitivity was similar to manual screening, while ACIS detected fewer cells (P < 0.001, McNemar's test). CONCLUSIONS: All protocols resulted in AP-visualization of occasional hematopoietic cells. However, morphological classification brings the specificity to a satisfactory high level. Approximately 10% of AP-visualized cells were categorized "questionable". The CK2 protocol turned out less specific than the A45-B/B3 and AE1AE3 protocols.

Detection of isolated tumor cells in peripheral blood and in BM: evaluation of a new enrichment method.

Cell enrichment methods that deal with larger volumes of peripheral blood and BM are needed for increased sensitivity of detection, characterization and quantification of isolated tumor cells (ITC). This study was designed to evaluate a new procedure, the RosetteSep-Applied Imaging Rare Event (RARE) detection method, which depletes the majority of the erythrocytes and leucocytes in a peripheral blood (PB) sample, thereby negatively enriching tumor cells if present. This enrichment procedure allows for increased sensitivity, by analyzing a 5-10 fold larger volume of blood, compared with a direct immunocytochemical (ICC) technique, with minimal impact on laboratory workload. Model experiments showed comparable tumor cell recoveries between the two tested methods, both in PB and BM. Clinical samples were evaluated using paired PB and BM samples from 95 carcinoma patients. Analysis of PB results showed that 25.3% had > or = 1 tumor cell detected by the RARE procedure, compared with 5.2% after direct ICC analysis, analyzing a 10-fold larger volume by the RARE procedure. The direct ICC analysis of BM from the same patients revealed 16.8% positive. The ITC detection differed both quantitatively and qualitatively between BM and PB, as samples with high numbers of ITC in BM were still negative in PB. The clinical significance of ITC in blood still needs to be established. However, the easy access of peripheral blood, and the increased sensitivity obtained by increasing the sample volume with the RARE procedure, suggests that the value of peripheral blood analysis should be tested in parallel in studies where ITC detection in BM is performed.

Detection of isolated tumor cells in bone marrow is an independent prognostic factor in breast cancer.

PURPOSE: This study was performed to disclose the clinical impact of isolated tumor cell (ITC) detection in bone marrow (BM) in breast cancer. PATIENTS AND METHODS: BM aspirates were collected from 817 patients at primary surgery. Tumor cells in BM were detected by immunocytochemistry using anticytokeratin antibodies (AE1/AE3). Analyses of the primary tumor included histologic grading, vascular invasion, and immunohistochemical detection of c-erbB-2, cathepsin D, p53, and estrogen receptor (ER)/progesterone receptor (PgR) expression. These analyses were compared with clinical outcome. The median follow-up was 49 months. RESULTS: ITC were detected in 13.2% of the patients. The detection rate rose with increasing tumor size (P =.011) and lymph node involvement (P <.001). Systemic relapse and death from breast cancer occurred in 31.7% and 26.9% of the BM-positive patients versus 13.7% and 10.9% of BM-negative patients, respectively (P <.001). Analyzing node-positive and node-negative patients separately, ITC positivity was associated with poor prognosis in the node-positive group and in node-negative patients not receiving adjuvant therapy (T1N0). In multivariate analysis, ITC in BM was an independent prognostic factor together with node, tumor, and ER/PgR status, histologic grade, and vascular invasion. In separate analysis of the T1N0 patients, histologic grade was independently associated with both distant disease-free survival (DDFS) and breast cancer-specific survival (BCSS), ITC detection was associated with BCSS, and vascular invasion was associated with DDFS. CONCLUSION: ITC in BM is an independent predictor of DDFS and BCSS. An unfavorable prognosis was observed for node-positive patients and for node-negative patients not receiving systemic therapy. A combination of several independent prognostic factors can classify subgroups of patients into excellent and high-risk prognosis groups.

Detection of isolated tumor cells in BM from breast-cancer patients: significance of anterior and posterior iliac crest aspirations and the number of mononuclear cells analyzed.

BACKGROUND: The aim of this study was to determine the influence and significance of different aspiration sites and the number of mononuclear cells (MNC) analyzed on the frequency of isolated tumor cell (ITC) detection by immunocytochemistry (ICC) in BM aspirates from breast-cancer patients. METHODS: BM aspirates were collected from the two anterior and two posterior crests just prior to primary surgery. The BM was processed separately from the anterior and the posterior crests, and cytospins (2 x 10(6) MNC) were prepared for ICC examination. The remaining cells were pooled, followed by cytospin preparation and ICC analysis (2 x 10(6) MNC/test). In addition, a fraction of the pooled cells were further processed by negative immunomagnetic selection, for enrichment of ITC. Out of 100 patients selected, 97 were further analyzed. RESULTS: The ICC examination from the separate crests revealed 37 positive BMs from the anterior iliac crest and 30 positive from the posterior crest. Twenty-one of the samples were positive at both sides. Five patients had 10 or more ITCs detected. In these, an unequal distribution of ITCs between the sides was observed, but in favor of neither. ICC analysis of 2, 4 and 6 x 10(6) MNC revealed respectively 22, 46 and 52 positive BMs out of the 97 analyzed. These results were correlated to the clinical outcome after a median 43 months follow-up. Thirteen of the patients underwent systemic relapse. Analyzing 2 x 10(6) MNC by ICC, 27.3% of the BM+ patients developed systemic disease, compared with 9.3% of the BM+ patients (P = 0.0056, log rank test). Analyzing 6 x 10(6) MNC reduced the correlation between ITC in BM and clinical outcome. CONCLUSION: No significant difference in the detection rate of ITCs from the anterior and the posterior iliac crests was found, although the distribution of ITCs did show a great variability. Analyzing a higher number of BM cells increased the number of positive BM specimens detected. However, this increased detection rate reduces the prediction by ICC of early systemic relapse.

Detection of isolated tumor cells in bone marrow in early-stage breast carcinoma patients: comparison with preoperative clinical parameters and primary tumor characteristics.

UNLABELLED: PURPOSE/EXPERIMENTAL DESIGN: The importance of detection of disseminated isolated tumor cells (ITCs) in bone marrow (BM) is still not settled. BM aspirates from 920 patients with primary breast cancer were analyzed for tumor cells by standardized direct immunocytochemical analysis (ICC) of 2 x 10(6) mononuclear cells (MNCs) using anticytokeratin monoclonal antibody (AE1/AE3). Samples (637) were analyzed by negative immunomagnetic enrichment (IMS) followed by ICC (10 x 10(6) MNCs). Analyses of the primary tumor specimens have been performed, including histomorphology, tumor-node-metastasis (TNM) staging, grading, and immunohistochemical analyses. RESULTS: Of the patients with infiltrating carcinoma, 63% were node negative (N0) and 33%, node positive (N+). The results show the presence of tumor cells in 13.4% of the evaluable patients after direct ICC analysis. The presence of tumor cells correlated to the nodal- and tumor stage, showing BM positivity in 9.9% of the N0 cases and 20.6% in the N+ group (P < 0.0005), 11.2% of the stage T(1) were positive, and 15.0% and 22.6% were positive in the T(2) and T(3/4) groups, respectively (P = 0.013). No correlation between detection of ITC and detection of p53 and cathepsin D expression was found. Vascular invasion and c-erbB2 expression were associated with ITCs in BM (P = 0.045 and P = 0.024, respectively). Node-negative patients with estrogen receptor (ER)+ and/or progesterone receptor (PgR)+ tumors had lower frequency of ITCs than ER-/PgR- (P = 0.004). The use of negative IMS increased the frequency of positive BM by 63% (P < 0.0005). CONCLUSIONS: The direct ICC detection of ITCs in BM correlated with primary tumor stage, nodal stage, vascular invasion, c-erbB2 expression, and ER/PgR status. Analysis of larger BM samples by negative IMS resulted in increased number of ITC-positive patients.

Use of automated microscopy for the detection of disseminated tumor cells in bone marrow samples.

The use of automated microscopy has reached the maturity necessary for its routine use in the clinical pathology laboratory. In the following study we compared the performance of an automated microscope system (MDS) with manual method for the detection and analysis of disseminated tumor cells present in bone marrow preparations from breast carcinoma patients. The MDS System detected rare disseminated tumor cells among bone marrow mononuclear cells with higher sensitivity than standard manual microscopy. Automated microscopy also proved to be a method of high reproducibility and precision, the advantage of which was clearly illustrated by problems of variability in manual screening. Accumulated results from two pathologists who had screened 120 clinical slides from breast cancer patients both by manual microscopy and by use of the MDS System revealed only two (3.8%) missed by the automatic procedure, whereas as many as 20 out of 52 positive samples (38%) were missed by manual screening.

Micrometastasis to axillary lymph nodes and bone marrow in breast cancer patients.

The axillary lymph nodes of 100 lymph node-negative breast cancer patients with known bone marrow status have been re-examined to explore the presence of micrometastasis in lymph nodes and the covariance of micrometastasis to bone marrow and lymph nodes. Nodes were serially sectioned at three intervals of 100 microm, followed by immunohistological (two sections) and haematoxylin-eosin staining (one section). Tumours were mainly T1 and T2, and the patients had on average 13 (4-22) lymph nodes removed. In two patients, micrometastasis was detected in one node. Another 25 patients possessed single positive immunostained cells mimicking tumour cells. These cells have been shown to be false positive cells by Perl and melanin staining. One patient had metastasis to several nodes missed by the original examination. Immunocytochemical detection of micrometastasis in bone marrow revealed 11 marrow-positive patients. This study has identified a low frequency of micrometastasis to lymph nodes, and no covariance with micrometastasis in the bone marrow was seen. Bone marrow micrometastasis may be an independent prognostic variable, separate from axillary node status.

Minimal residual disease in breast cancer.

The incidence of breast cancer is increasing dramatically in the developed countries. Although attention is being paid to diagnose breast cancer early through screening programs, still a significant number of patients classified to have a localised disease at diagnosis, later experience a systemic recurrence. Therefore, more sensitive and reliable methods to detect the early spread of the disease, permitting the early use of additional systemic therapy, seem justified. New treatment strategies, such as immunotherapy employing monoclonal antibodies against breast cancer cells, is promising. Since such a treatment is most efficient on patients with limited disease, sensitive methods to monitor the therapeutic effect are needed. Immunocytochemistry using tumour associated monoclonal antibodies and reverse transcription polymerase chain reaction assays (RT-PCR), that screen for carcinoma-specific expression of mRNA in bone marrow and blood, have been developed. Many standardisation problems with the detection methods currently in use are unsolved. Despite this, we discuss here recent data showing that the presence of occult tumour cells in the bone marrow is a prognostic factor in patients with breast cancer.

Standardization of the immunocytochemical detection of cancer cells in BM and blood: I. establishment of objective criteria for the evaluation of immunostained cells.

BACKGROUND: Detection of isolated tumor cells (TC) in BM from carcinoma patients can predict future relapse. Various molecular and immunocytochemical (ICC) methods have been used to detect these cells, which are present at extremely low frequencies of 10(-5) - 10(-6). The specificity and sensitivity of these techniques may vary widely. In 1996, a European ISHAGE Working Group was founded to standardize and optimize procedures used for the detection of minimal residual disease. We have attempted to develop objective criteria for the evaluation of immunocytochemically identifiable cancer cells. METHODS: An interlaboratory ring experiment was performed, to compare the screening and detection of micrometastasis-positive events between different laboratories. The discrepant results induced us to establish a common consensus on morphological criteria applicable to the identification of immunostained micrometastatic TC. RESULTS: Bared on this consensus evaluation, we propose a classification of stained elements into three groups: (1) 'TC's show pathognomonic signs of epithelial TC-nature, as defined by a clearly enlarged nucleus or clusters of > or = 2 immunopositive cells. (2) 'Probable TC's represent morphological overlap between hematopoietic cells (HC) and TC which lack pathognomonic signs of TC-nature, but do not exhibit clear morphological features of HC. These cells are considered as TC if control staining with an isotype-specific, unrelated Ab is negative. (3) 'TC-negative' cells are defined as 'false positive' HC, skin squamous epithelial cells and artefacts. DISCUSSION: The proposed classification of immunostained events is a first step towards the development of standardized immunocytochemical assays for the detection of occult micrometastatic TC in BM or blood.

Immunocytochemical detection of isolated epithelial cells in bone marrow: non-specific staining and contribution by plasma cells directly reactive to alkaline phosphatase.

Detection of isolated tumour cells (TCs) in bone marrow (BM) from epithelial cancer patients by immunocytochemical (ICC) analysis seems to predict future relapse, but the reported percentages of positive BMs among patients with localized cancer show large variations and the number of detected TCs is low. This emphasizes the importance of thoroughly testing the methods in use. This study was performed to clarify to what extent positive staining of haematopoietic cells (HCs) interferes with the ICC detection of epithelial cells in BM. BM mononuclear cells (MNCs) from normal donors and stage I-II breast cancer patients were stained with anti-cytokeratin (CK) and isotype control monoclonal antibodies (MAbs) followed by alkaline phosphatase (AP)-based visualization of immunolabelled cells. In the ICC staining of normal donors by the anti-CK MAbs AE1/AE3 or A45-B/B3, rare immunoreactive cells were detected in 7/20 and 8/19 BMs, respectively. Morphological examination recognized all these cells as typical HCs. In the breast cancer patients (n = 257), anti-CK-positive cells were detected in 26.6 per cent, excluding cells with HC morphology. Using the same morphological criteria, isotype control-positive cells were detected in 5.4 per cent of patients. Some of the false-positive events were further analysed and cells with strong reactivity against the AP enzyme alone were detected. Double ICC staining recognized the majority of these AP directly-reactive cells as CD45-negative and human Ig kappa/lambda-positive, in accordance with the phenotype of mature plasma cells. Morphological evaluation and adequate controls are important to ensure the diagnostic specificity of micrometastases in BM. It is recommended that the number of BM MNCs included in negative controls should equal the number of cells in the diagnostic specimens.

Increased sensitivity for detection of micrometastases in bone-marrow/peripheral-blood stem-cell products from breast-cancer patients by negative immunomagnetic separation.

Immunocytochemical detection (ICC) of isolated tumor cells in bone marrow (BM) is currently the most established method for monitoring early dissemination in epithelial cancer. However, the low sample size that can practically be analyzed restricts the sensitivity and reliability of the ICC method. To be able to analyze larger samples, a negative immunomagnetic separation (IMS) technique, utilising anti-CD45-conjugated Dynabeads, has been developed. Tumor-cell enrichment by depletion of CD45-expressing mononuclear cells (MNC) is followed by ICC for detection of the cytokeratin (CK)-positive (+) epithelial cells. In this study, bone-marrow samples (n = 165) and peripheral-blood-progenitor-cell (PBPC) apheresis products (n = 22) from breast-cancer patients were analyzed. The negative IMS analysis of 1 to 2 x 10(7) MNC was compared with ICC analysis of 2 x 10(6) unseparated MNC. Negative IMS resulted in 85% mean depletion of MNC. The results showed that 11.7% of the samples were positive by ICC analysis of unseparated MNC, as compared with 23.5% after negative IMS. In samples presenting > 10 CK+ cells, a 4-fold higher number of positive cells was detected by the negative IMS technique. Moreover, there was no evidence for general enrichment of false-positive cells. Altogether our results show that negative IMS is an efficient enrichment method for sensitive detection of CK+ cells in BM/PBPC products from breast-cancer patients. This opens the possibility for further characterization of micrometastatic tumor cells.