Detection of circulating tumor cells and micrometastases in stage II, III, and IV breast cancer patients utilizing cytology and immunocytochemistry

Detection of Circulating Tumor Cells in Resectable Pancreatic Ductal Adenocarcinoma: A Prospective Evaluation as a Prognostic Marker

Circulating tumor cells (CTCs) are useful biomarkers of many solid tumors, but are infrequently detected in early stage pancreatic ductal adenocarcinomas (PDACs). The first drainage of pancreatic venous blood flow come to portal vein and pass through the liver, and they finally go out for peripheral blood. We thought that comparing CTCs from portal vein and peripheral blood could enable us to understand the clinical meaning of CTCs from each different site in PDACs. Therefore, we aimed to determine 1) whether CTCs could be reliably identified in early stages (operable) of PDACs, 2) if there are any differences in the detected number of CTC in portal vein blood and peripheral blood, and 3) whether CTCs can be sensitive biomarkers for the prognosis of resectable PDAC patients. Newly diagnosed PDAC patients who underwent operation with curative intention between 2013 and 2015 were prospectively enrolled. Blood draws from portal and peripheral vein ran through the microfabricated porous filter, and anti-epithelial cell adhesion molecule (EpCAM) and anti-Plectin-1 antibodies were used for CTC identification. Baseline clinical characteristics, tumor characteristics, treatment, and clinical outcomes were assessed. The clinical stages of the 32 enrolled patients were as follows: IA/IB 1 (3.1%); IIA 9 (28.1%); IIB 17 (53.1%); III 5 (15.6%). Twenty-seven patients (84.4%) received R0 resection, while five patients (15.6%) received R1 resection. EpCAM+ CTCs were detected in 20 portal blood (62.5%) and 22 peripheral blood (68.8%). Plectin-1+ CTCs were identified in 14 portal blood (43.8%) and 16 peripheral blood (50%). Plectin-1-expressing CTCs were picked from CTC platform (microfabricated porous filter) and we could find out all KRAS mutation. Patients with detectable EpCAM+ CTC less than one in peripheral blood showed longer overall survival (OS) compared to patients with detectable CTCs more than one (35.5 months vs. 16.0 months). EpCAM and Plectin-1 successfully identified CTCs at the early stage of PDACs. Also, the number of CTCs could be a prognostic marker for survival in resectable PDACs.

Circulating tumor cells predict survival benefit from chemotherapy in patients with lung cancer

Background

This meta-analysis was to explore the clinical significance of circulating tumor cells (CTCs) in predicting the tumor response to chemotherapy and prognosis of patients with lung cancer.

Methods

We searched PubMed, Embase, Cochrane Database, Web of Science and reference lists of relevant articles. Our meta-analysis was performed by Stata software, version 12.0, with a random effects model. Risk ratio (RR), hazard ratio (HR) and 95% confidence intervals (CI) were used as effect measures.

Results

8 studies, including 453 patients, were eligible for analyses. We showed that the disease control rate (DCR) in CTCs-negative patients was significantly higher than CTCs-positive patients at baseline (RR = 2.56, 95%CI [1.36, 4.82], p < 0.05) and during chemotherapy (RR = 9.08, CI [3.44, 23.98], p < 0.001). Patients who converted form CTC-negative to positive or persistently positive during chemotherapy had a worse disease progression than those with CTC-positive to negative or persistently negative (RR = 8.52, CI [1.66, 43.83], p < 0.05). Detection of CTCs at baseline and during chemotherapy also indicated poor overall survival (OS) (baseline: HR = 3.43, CI [2.21, 5.33], p<0.001; during chemotherapy: HR = 3.16, CI [2.23, 4.48], p < 0.001) and progression-free survival (PFS) (baseline: HR = 3.16, 95%CI [2.23, 4.48], p < 0.001; during chemotherapy: HR = 3.78, CI [2.33, 6.13], p < 0.001).

Conclusions

Detection of CTCs in peripheral blood indicates poor tumor response to chemotherapy and poor prognosis in patients with lung cancer.

Predictive Value of Circulating Tumor Cells for Evaluating Short- and Long-Term Efficacy of Chemotherapy for Breast Cancer

BACKGROUND The present study investigated the role of circulating tumor cells (CTCs) counts in predicting the short- and long-term efficacy of chemotherapy for breast cancer (BC). MATERIAL AND METHODS Peripheral venous blood was extracted from 187 BC patients. CTCs were measured by flow cytometry. Spearman's correlation analysis was performed to examine the correlation between the efficacy of chemotherapy and CTC counts. A receiver operating characteristic (ROC) curve was plotted to estimate the predictive value of CTC counts. The Kaplan-Meier method was employed to calculate disease-free survival (DFS) and overall survival (OS). Cox regression analysis was used to determine risk factors for prognosis of BC. RESULTS Complete response (CR) + partial response (PR) was achieved by 65.8% of BC patients. After chemotherapy, CTC counts were decreased in both the CR + PR and SD + PD groups. Spearman's correlation analysis indicated that CTC counts before chemotherapy were positively correlated with clinical response to chemotherapy (r=0.45, P<0.05). For predicting clinical response to chemotherapy, CTC counts yielded an area under the curve (AUC) of 0.958, with sensitivity reaching 96.9% and specificity reaching 85.4%. The Kaplan-Meier method and Cox regression analysis indicated that tumor node metastasis (TNM) staging, lymph node metastasis (LNM), ki-67, endocrine therapy, and CTC counts were risk factors for prognosis of BC. CONCLUSIONS These findings indicate that BC patients with CTCs ³8 exhibited poor response to chemotherapy and poor OS. CTC counts can serve as an indicator in predicting short- and long-term efficacy of chemotherapy for BC.

Prognostic significance of circulating tumor cells in esophageal carcinoma: a meta-analysis

PURPOSE

The prognostic significance of circulating tumor cells (CTCs) in esophageal carcinoma (EC) is controversial. We aim to assess its association with clinicopathological and prognostic relevance in EC by using a meta-analysis.

METHODS

We searched PubMed, Cochrane Database, Embase databases, and the references in relevant studies that assessed the clinicopathological or prognostic relevance of CTCs in peripheral blood of patients with EC. Statistical analyses were conducted by using Stata software to calculate the pooled odds ratio (OR), hazard ratio (HR), and 95% confidence intervals (CIs) using fixed or random-effects models according to the heterogeneity of included studies. The subgroup analyses were performed according to ethnicity, histological type, and detection method.

RESULTS

Sixteen trials containing 1,260 patients were included for analysis. Pooled results showed that presence of CTCs was significantly associated with poor overall survival (HR =1.71, 95% CI [1.30, 2.12], P<0.001) and progression-free survival (HR =1.67, 95% CI [1.19, 2.15], P<0.001) in EC patients. Subgroup analysis indicated that presence of CTCs was closely associated with worse overall survival (Asian: HR =1.66, 95% CI [1.24, 2.08], P<0.001; squamous cell carcinoma [SCC]: HR =1.66, 95% CI [1.24, 2.08], P<0.001; no polymerase chain reaction [PCR]: HR =2.08, 95% CI [1.40, 2.76], P<0.001) and progression-free survival (Asian: HR =1.63, 95% CI [1.15, 2.12], P<0.001; SCC: HR =1.63, 95% CI [1.15, 2.12], P<0.001; PCR: HR =1.63, 95% CI [1.15, 2.12], P<0.001). Additionally, ORs showed that presence of CTCs was significantly correlated with tumor node metastasis (TNM) staging (overall: OR = 1.96, 95% CI [1.34, 2.87], P=0.001; Asian: OR =2.09, 95% CI [1.37, 3.19], P=0.001; SCC: OR =1.97, 95% CI [1.21, 3.07], P=0.003; PCR: OR =2.23, 95% CI [1.43, 3.47], P<0.001), venous invasion (overall: OR =2.23, 95% CI [1.46, 3.40], P<0.001; Asian: OR =2.23, 95% CI [1.46, 3.40], P<0.001; SCC: OR =2.23, 95% CI [1.46, 3.40], P<0.001; PCR: OR =2.23, 95% CI [1.46, 3.40], P<0.001), lymph node metastasis (overall: OR =2.41, 95% CI [1.50, 3.86], P<0.001; Asian: OR =2.89, 95% CI [1.80, 4.65], P<0.001; SCC: OR =2.44, 95% CI [1.47, 4.07], P=0.001; PCR: OR =2.89, 95% CI [1.80, 4.65], P<0.001) and distant metastasis (Asian: OR =2.68, 95% CI [1.01, 7.08], P=0.047) in patients with EC.

CONCLUSION

The presence of CTCs indicates a poor prognosis in EC patients, especially in Asian and SCC patients. Further well-designed prospective studies are recommended to explore the clinical applications of CTCs in patients with EC.

Prognostic significance of circulating tumor cells in non-small-cell lung cancer patients: a meta-analysis

Background

The prognostic significance of circulating tumor cells (CTCs) detected in patients with non-small-cell lung cancer (NSCLC) is still inconsistent. We aimed to assess the prognostic relevance of CTCs using a meta-analysis.

Methods

We searched PubMed, Web of Science and EMBASE for relevant studies that assessed the prognostic relevance of CTCs in NSCLC. Statistical analyses were conducted to calculate the summary incidence, odds ratio, relative risks (RRs) and 95% confidence intervals (CIs) using fixed or random-effects models according to the heterogeneity of included studies.

Results

A total of 20 studies, comprising 1576 patients, met the inclusion criteria. In identified studies, CTCs were not correlated with histology (adenocarcinoma vs squamous cell carcinoma) (odds ratio [OR]  =  0.88; 95% confidence interval [CI]: 0.59–1.33; Z = –0.61; P = 0.545). However, pooled analyses showed that CTCs were associated with lymph node metastasis (OR = 2.06; 95% CI: 1.18–3.62; Z = 2.20; P = 0.027) and tumor stage (OR  = 1.95; 95% CI: 1.08–3.54; Z = 2.53; P = 0.011). Moreover, CTCs were significantly associated with shorter overall survival (relative risk [RR]  = 2.19; 95% CI: 1.53–3.12; Z = 4.32; P<0.0001) and progression-free/disease-free survival (RR  = 2.14; 95% CI: 1.36–3.38; Z = 3.28; P<0.0001).

Conclusion

The presence of CTCs indicates a poor prognosis in patients with NSCLC. Further well-designed prospective studies are required to explore the clinical applications of CTCs in lung cancer.

Detection of disseminated tumor cells in locally advanced breast cancer patients before primary systemic therapy

AIM

To assess the prevalence and prognostic power of disseminated tumor cells (DTC) in patients with locally advanced breast cancer (LABC) before primary systemic therapy (PST).

MATERIALS AND METHODS

LABC patients attending our Breast Unit were studied between 2002 and 2012, all of them being considered for PST. To determine the presence of DTC, posterior iliac crest aspirates were obtained and marrow samples were processed by gradient separation with Ficoll (Lymphoprep(®)) and immunohistochemical staining using the antiCK A45-B/B3 (EPIMET) antibody. Clinicopathologic variables were recorded before and after PST to assess response. Disease-free survival (DFS) and overall survival (OS) were determined after follow-up. The presence of DTC as a predictor of response to PST and as a prognostic tool for OS and DSF was evaluated.

RESULTS

DTC were observed in 26% of 47 patients included in the study. PST consisted of chemotherapy in 94% and hormone therapy in 6%. Breast-conserving therapy was attained in 33%. Mean follow-up was 68 months. Complete clinical response (CR) after PST was seen in 26%, disease recurrence in 38%, and cancer-related death in 8%; tumor size and negative estrogen receptors were significant predictors of CR and mastectomy was associated with DFS. Persistent axillary disease after PST and previous recurrence were predictive of OS. DTC were detected more often in patients who did not achieve CR and those who presented recurrence. DTC detection was a significant prognostic factor for a worse OS (OR = 7.62; CI95%: 1.46-39.61; p = 0.009) and a decreased survival time (62 versus 82 months, p = 0.004).

CONCLUSION

Presence of DTC before PST was found in a significant number of patients with LABC. DTC were found to be a significant prognostic factor for cancer-related death. DTC could be a surrogate predictor of response to PST and also of disease recurrence in LABC patients.

Prognostic value of hematogenous dissemination and biological profile of the tumor in early breast cancer patients: a prospective observational study

Background

The aim of this study was to investigate the incidence and prognostic value of disseminated tumor cells in bone marrow of breast carcinoma patients with early disease, and to analyze this finding in relation to lymph node involvement, determined by sentinel lymph node (SLN) biopsy analysis, and to prognostic factors of interest.

Methods

104 patients with operable (T < 3 cm) breast cancer and clinically- and sonographically-negative axillary lymph nodes were scheduled for SLN biopsy. Bone marrow aspirates were collected before the start of surgery from both iliac crests, and mononuclear cell layers were separated by density centrifugation (Lymphoprep). Slide preparations were then examined for the presence of disseminated tumor cells by immunocytochemistry with anti-cytokeratin antibodies (A45-B/B3). Lymphoscintigraphy was performed 2 hours after intratumor administration of 2 mCi (74 MBq) of 99mTc colloidal albumin. The SLN was evaluated for the presence of tumor cells by hematoxylin-eosin staining and, when negative, by immunocytochemistry using anti-cytokeratin antibody (CAM 5.2). Survival analyses and comparative analyses were performed on the results of bone marrow determinations, SLN biopsy, and known prognostic factors, including breast cancer subtypes according to the simplified classification based on ER, PR and HER2.

Results

Lymph node and hematogenous dissemination occur in one-third of patients with early-stage breast cancer, although not necessarily simultaneously. In our study, disseminated tumor cells were identified in 22% of bone marrow aspirates, whereas 28% of patients had axillary lymph node involvement. Simultaneous lymph node and bone marrow involvement was found in only 5 patients (nonsignificant). In the survival study (60 months), a higher, although nonsignificant rate of disease-related events (13%) was seen in patients with disseminated tumor cells in bone marrow, and a significant association of events was documented with the known, more aggressive tumor subtypes: triple negative receptor status (21%) and positive ERBB2 status (29%).

Conclusions

Tumor cell detection in bone marrow can be considered a valid prognostic parameter in patients with early disease. However, the classic prognostic factors remain highly relevant, and the newer breast cancer subtypes are also useful for this purpose.

High-throughput size-based rare cell enrichment using microscale vortices

Cell isolation in designated regions or from heterogeneous samples is often required for many microfluidic cell-based assays. However, current techniques have either limited throughput or are incapable of viable off-chip collection. We present an innovative approach, allowing high-throughput and label-free cell isolation and enrichment from heterogeneous solution using cell size as a biomarker. The approach utilizes the irreversible migration of particles into microscale vortices, developed in parallel expansion-contraction trapping reservoirs, as the cell isolation mechanism. We empirically determined the critical particle∕cell diameter D(crt) and the operational flow rate above which trapping of cells∕particles in microvortices is initiated. Using this approach we successfully separated larger cancer cells spiked in blood from the smaller blood cells with processing rates as high as 7.5×10(6) cells∕s. Viable long-term culture was established using cells collected off-chip, suggesting that the proposed technique would be useful for clinical and research applications in which in vitro culture is often desired. The presented technology improves on current technology by enriching cells based on size without clogging mechanical filters, employing only a simple single-layered microfluidic device and processing cell solutions at the ml∕min scale.

Morphological analysis of circulating tumour cells in patients undergoing surgery for non-small cell lung carcinoma using the isolation by size of epithelial tumour cell (ISET) method

BACKGROUND AND OBJECTIVE

Recurrence rates after surgery for non-small cell lung cancer (NSCLC) range from 25 to 50% and 5-year survival is only 60-70%. Because no biomarkers are predictive of recurrence or the onset of metastasis, pathological TNM (pTNM) staging is currently the best prognostic factor. Consequently, the preoperative detection of circulating tumour cells (CTCs) might be useful in tailoring therapy. The aim of this study was to characterize morphologically any circulating non-haematological cells (CNHCs) in patients undergoing surgery for NSCLC using the isolation by size of epithelial tumour cell (ISET) method.

METHODS

Of 299 blood samples tested, 250 were from patients with resectable NSCLC and 59 from healthy controls. The presence of CNHCs was assessed blindly and independently by 10 cytopathologists on May-Grünwald-Giemsa stained filters and the cells classified into three groups: (i) malignant cells, (ii) uncertain malignant cells, and (iii) benign cells. We assessed interobserver agreement using Kappa (κ) analysis as the measure of agreement.

RESULTS

A total of 123 out of 250 (49%) patients showed CNHCs corresponding to malignant, uncertain malignant and benign cells, in 102/250 (41%), 15/250 (6%) and 6/250 (2%) cases, respectively. No CNHCs were detected in the blood of healthy subjects. Interobserver diagnostic variability was absent for CNHCs, low for malignant cells and limited for uncertain malignant and benign cells.

CONCLUSION

Identification of CTCs in resectable NSCLC patients, using ISET technology and according to cytopathological criteria of malignancy, appears to be a new and promising field of cytopathology with potential relevance to lung oncology.

Circulating tumor cells: a useful predictor of treatment efficacy in metastatic breast cancer

PURPOSE

Five or more circulating tumor cells (CTCs) per 7.5 mL of blood predicts for poorer progression-free survival (PFS) in patients with metastatic breast cancer (MBC). We conducted a prospective study to demonstrate that CTC results correlate strongly with radiographic disease progression at the time of and in advance of imaging.

PATIENTS AND METHODS

Serial CTC levels were obtained in patients starting a new treatment regimen for progressive, radiographically measurable MBC. Peripheral blood was collected for CTC enumeration at baseline and at 3- to 4-week intervals. Clinical outcomes were based on radiographic studies performed in 9- to 12-week intervals.

RESULTS

Sixty-eight patients were evaluable for the CTC-imaging correlations, and 74 patients were evaluable for the PFS analysis. Median follow-up was 13.3 months. A statistically significant correlation was demonstrated between CTC levels and radiographic disease progression in patients receiving chemotherapy or endocrine therapy. This correlation applied to CTC results obtained at the time of imaging (odds ratio [OR], 6.3), 3 to 5 weeks before imaging (OR, 3.1), and 7 to 9 weeks before imaging (OR, 4.9). Results from analyses stratified by type of therapy remained statistically significant. Shorter PFS was observed for patients with five or more CTCs at 3 to 5 weeks and at 7 to 9 weeks after the start of treatment.

CONCLUSION

We provide, to our knowledge, the first evidence of a strong correlation between CTC results and radiographic disease progression in patients receiving chemotherapy or endocrine therapy for MBC. These findings support the role of CTC enumeration as an adjunct to standard methods of monitoring disease status in MBC.

Recent advances in the detection of bone marrow micrometastases: A promising area for research or just another false hope? A review of the literature

The presence of early disseminated tumor cells (DTC), otherwise termed micrometastases or minimal residual disease, in the bone marrow (BM), or other secondary compartments, such as the blood and the lymph nodes, is the main reason for recurrence of patients with early stage epithelial cancers after "curative" resection of the primary tumor. There is increasing evidence, that the detection of DTC in BM aspirates may provide additional and independent prognostic information and aid in the stratification of these patients for adjuvant clinical treatment. However, the clinical relevance of micrometastases has not yet been firmly established. In addition, the molecular events and interactions that prevail in early metastatic disease and determine the formation or not of overt metastases remain poorly understood. The methods currently used for the detection of micrometastatic cells include extremely sensitive immunocytochemical and molecular assays, often in conjunction with enrichment techniques for the purification of tumor cells and additional increase of their sensitivity. Nevertheless, the specificity of these methods is mostly inadequate. After the impressive advances of molecular cytogenetics, a highly accurate and global assessment of the genetic status of tumors is now possible. Therefore, the greatest challenge of our time is the application of these novel technologies for the clarification of the key molecular events that initiate metastatic spread. This will further enable us to identify the highly specific and sensitive diagnostic and prognostic markers as well as the therapeutic targets which are so urgently needed.

Tumor cell detection in peripheral blood and bone marrow

PURPOSE OF REVIEW

Whether the occurrence of tumor cells in peripheral blood or bone marrow from patients with solid tumors is predictive for disease recurrence or of any other prognostic relevance remains unknown. This article reviews recently published results focusing on the various methods used, their correlations with clinical or biological parameters and their potential prognostic value.

RECENT FINDINGS

An increasing number of marker genes and different techniques, alone or in combinations, have been used for the detection of tumor cells in peripheral blood and bone marrow. Various results obtained are hardly comparable, most often due to the different methods in use. The frequency of circulating tumor cells in peripheral blood varied within a broad range and their clinical relevance appeared to be contradictory, at least in part. Disseminated tumor cells in bone marrow reached an independent prognostic value in breast cancer patients, but several investigations led to inconsistent correlations with clinical or prognostic criteria.

SUMMARY

Still many questions remain unanswered; hence, the detection of tumor cells in peripheral blood or bone marrow cannot yet be taken into account for therapeutic decisions.

Occult tumor cell contamination in patients with stage II/III breast cancer receiving sequential high-dose chemotherapy

The purpose of this study was to evaluate the presence of micrometastatic cells in the apheresis products from patients with breast cancer, and also to determine if repeated infusion of contaminated products had any clinical impact. A total of 94 patients with high-risk breast cancer were enrolled in a prospective single center study to evaluate the use of dose-intensified chemotherapy (doxorubicine 75 mg/m(2) and cyclophosphamide 3000 or 6000 mg/m(2) for four cycles) with repeated (x 2) stem cell reinfusion. All women were monitored for the presence of metastatic cells in aphereses, collected after first course of intensive chemotherapy, and following additional mobilization with rhG-CSF. Epithelial cells were screened with monoclonal antibodies directed to cytokeratin. Eight of the 94 patients had detectable tumor cells in one or several aphereses collected after intensive chemotherapy; this was unrelated to other tumor characteristics, including size, histology, Scarff Bloom and Richardson (SBR) grading (presence or absence of hormone receptors). Hemato-poietic reconstitution was similar in the cells from these eight patients, and in the total patient population. Three of these eight patients relapsed. This study has confirmed that contamination of apheresis products remains a rare event, which does not seem to affect clinical evolution, even when reinfused into the patient.

Micrometastases in apheresis products predict shorter progression-free and overall survival in patients with breast cancer undergoing high-dose chemotherapy (HDCT) and autologous blood stem cell transplantation (ABSCT)

The presence of cancer cells in autografts of breast cancer patients has been described to have prognostic value or directly lead to relapse. Previously, we demonstrated that apheresis products (APs) collected after induction chemotherapy have a significantly lower likelihood of tumor cell contamination. Here, we examine the prognostic value of micrometastases in autografts. Data from 83 patients with breast cancer treated with autologous blood stem cell transplantation were analyzed. Pan-cytokeratin-FITC conjugated antibodies were used to detect contaminating breast cancer cells in the APs. Progression and survival data analyzed on the basis of three or fewer cancer cells showed no significant differences in outcomes. Of the 83 patients, 11 had more than three cancer cells detectable in their APs. In total, 72 patients were shown to have less than three cells detectable. When patients with more than three cells were compared to patients with 0-3, we found statistically significant differences in progression-free survival. We also found a significant difference in overall survival (OS) between the two groups. No difference was observed in OS since the time of diagnosis. We conclude that patients with more than three contaminating cells in their APs have micrometastases and represent a poor prognosis group.

Disseminated tumor cells in the bone marrow - chances and consequences of microscopical detection methods

The detection of disseminated tumor cells (DTCs) in the hematopoetic system is important for various reasons. It is essential for tumor staging. According to the International Neuroblastoma Staging System (INSS) only the cytomorphological examination of bone marrow smears is accepted despite the fact that an infiltrate below 0.1%, can hardly be detected and even infiltrates of more than 10% are sometimes overlooked. Another important aspect is the monitoring of the disease response to cytotoxic drugs by quantifying DTCs. Moreover, bone marrow aspirates represent an ideal source to determine the genetic and biological make up of DTCs at diagnosis and during follow up. Key issues that can be tested on DTCs are: determination of the proliferation capacity, the apoptotic rate, the drug sensitivity etc. The prerequisite for such a bone-marrow diagnosis, however, is the unequivocal identification of disseminated tumor cells. Thus, in order to avoid false positive and false negative results, which are a risk in bone-marrow diagnostics, a system was developed to distinguish tumor cells from non-neoplastic cells and to facilitate the gain of insights into the biological make-up of tumor cells more easily.

What the clinician needs from the pathologist: evidence-based reporting in breast cancer

Histopathology has a vital role in determining breast cancer management and pathologists must be part of the clinical team. Carcinoma size, grade, and especially lymph node status remain the best available prognostic factors. Metastatic carcinoma in axillary nodes is more important than any other prognostic factor presently available. ER status is an important predictor of response to endocrine manipulation, but its independent prognostic significance, and that of micrometastatic disease, circulating carcinoma cells and other molecular factors, even well-studied ones such as HER2 status, are less clear. Pathology is the first clinical speciality to subject its practice to rigorous scientific analysis, and it has stood up well. However, workers without appropriate experience in Pathology or scientific design have created difficulties by undertaking poorly planned studies with ill-defined end-points, lacking appropriate quality control. New analytical techniques and therapeutic targets make it essential that we learn from past mistakes and integrate pathologists into the research teams pursing clinical trials and the assessment of new bio-markers. Without this, input resource will be wasted on false leads that could have been curtailed. Morphology alone will not be enough to select patients likely to benefit in trials of new therapies, but selection 'tests' must be appropriate. The confusion of tests for selection of patients to receive Herceptin shows what happens when this process fails. Much of the microarray data being put into data-bases has no quality control, and meta-analysis of this data will produce even more conflict than the clinical trials. This can be avoided, as the ability to standardise is available.