Correction: Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemia.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Minimal residual disease quantification by flow cytometry provides reliable risk stratification in T-cell acute lymphoblastic leukemia.

Minimal residual disease (MRD) measured by PCR of clonal IgH/TCR rearrangements predicts relapse in T-cell acute lymphoblastic leukemia (T-ALL) and serves as risk stratification tool. Since 10% of patients have no suitable PCR-marker, we evaluated flowcytometry (FCM)-based MRD for risk stratification. We included 274 T-ALL patients treated in the NOPHO-ALL2008 protocol. MRD was measured by six-color FCM and real-time quantitative PCR. Day 29 PCR-MRD (cut-off 10-3) was used for risk stratification. At diagnosis, 93% had an FCM-marker for MRD monitoring, 84% a PCR-marker, and 99.3% (272/274) had a marker when combining the two. Adjusted for age and WBC, the hazard ratio for relapse was 3.55 (95% CI 1.4-9.0, p = 0.008) for day 29 FCM-MRD ≥ 10-3 and 5.6 (95% CI 2.0-16, p = 0.001) for PCR-MRD ≥ 10-3 compared with MRD < 10-3. Patients stratified to intermediate-risk therapy on day 29 with MRD 10-4-<10-3 had a 5-year event-free survival similar to intermediate-risk patients with MRD < 10-4 or undetectable, regardless of method for monitoring. Patients with day 15 FCM-MRD < 10-4 had a cumulative incidence of relapse of 2.3% (95% CI 0-6.8, n = 59). Thus, FCM-MRD allows early identification of patients eligible for reduced intensity therapy, but this needs further studies. In conclusion, FCM-MRD provides reliable risk prediction for T-ALL and can be used for stratification when no PCR-marker is available.

Discontinuous deletions at 11q23 in B cell chronic lymphocytic leukemia.

Loss of genomic material in 11q is one of the most common structural chromosome aberrations in B cell chronic lymphocytic leukemia (B-CLL). In order to characterize the deletions of 11q23 in B-CLL, we performed fluorescence in situ hybridization (FISH) with eight YAC (yeast artificial chromosome) probes on peripheral leukocytes of 30 patients. These YACs form a contig spanning 7.8 Mb at 11q23.1-q23.3. We found deletions in nine out of 30 cases (30%) and five of them had discontinuous deletions in this region. The region represented by YAC 755b11 (1.6 Mb in size) was involved in all cases with deletions, supporting the hypothesis that this region might contain a novel gene of pathogenic importance to B-CLL. A more distal region represented by YAC 785e12 (760 kb in size) was deleted frequently and specifically. Whether there is another novel gene of pathogenic importance to B-CLL and what is its potential relationship to the deletions in the region represented by YAC 755b11, are issues that require further studies.

Optimized mitogen stimulation induces proliferation of neoplastic B cells in chronic lymphocytic leukemia: significance for cytogenetic analysis.The Tampere Chronic Lympocytic Leukemia group.

We tested the effects of interleukin-2 (IL-2), human recombinant tumor necrosis factor alpha (TNF-alpha), Staphylococcus aureus Cowan I (SAC), TPA, and their combinations, using a standard thymidine incorporation assay, in order to identify an optimal mitogen combination (OMC) for 24 consecutive patients with B-cell chronic lymphocytic leukemia (B-CLL). The combination that induced the highest thymidine incorporation was chosen as the OMC for each patient. Among 14 mitogen combinations tested, there were six different OMCs, of which the most frequent was TNF-alpha + IL-2. It was the OMC in 9 of 24 cases. The other OMCs were TNF-alpha + TPA1 (5/24), SAC + IL-2 (5/24), TPA1 + IL-2 (3/24), TPA10 + IL-2 (1/24), and TNF-alpha + TPA10 + IL-1 (1/24). The mitogenic power of the selected OMC in each case was then evaluated both by the combination of immunophenotyping and molecular cytogenetic techniques known as MAC (Morphology, Antibody, Chromosomes) and standard chromosome analysis. After OMC stimulation, the levels of DNA synthesis and B-cell proliferation (mitotic index) were, on average, 10-fold higher than those observed after standard TPA stimulation (P < 0. 0001). The proportion of mitotic B cells exceeded the proportion of mitotic T cells in 70.1% of the cases after OMC stimulation. After TPA stimulation, 7.7% +/- 2.5% of all mitoses were B-cell mitoses, whereas after OMC stimulation this proportion rose to 57.9% +/- 5.3%. The frequency of clonal chromosomal aberrations increased from 46% after TPA stimulation to 79% after OMC stimulation. The clonal aberrations del(6q), del(11q), and/or del(13q) were observed in 26%, 32%, and 42% of the patients with the respective clonal chromosomal aberrations, whereas the corresponding frequencies after TPA stimulation were only 4%, 21%, and 17%. When the lineage involvement of cells with clonal chromosomal aberrations from three patients was analyzed, the aberrations were found to be restricted to B cells only, and in one patient to a minor subset of B cells. The results demonstrate that an individually chosen OMC induces a high rate of proliferation in neoplastic B cells. We found deletions in 6q, 11q, and 13q at higher frequencies than reported previously, most probably as a result of an improved mitogenic response. The identification of an optimal mitogen stimulation for each patient, prior to chromosome analysis, can well be expected to reduce the rate of false-normal results in the future. This is essential for accurate evaluation of the prognostic significance of chromosomal aberrations in B-CLL.

Reduced E-cadherin expression is associated with invasiveness and unfavorable prognosis in breast cancer.

E-cadherin (E-cad) is a calcium-dependent, epithelial cell adhesion molecule whose reduced or lost expression has been associated with tumor dedifferentiation and increased metastatic potential in human carcinomas. The authors studied immunohistochemically E-cad expression in frozen sections of 362 breast carcinomas using a monoclonal antibody (HECD-1). The immunohistochemical detection of reduced E-cad expression was confirmed by mRNA in situ hybridization with two different oligonucleotide probes. THe proportion of tumors with reduced or lost E-cad expression increased significantly from pure intraductal carcinomas (20%, 4 of 20) through invasive ductal (IDCs; 52%, 124 of 239) to recurrent carcinomas (64%, 18 of 28; chi square test for trend, P = .004). Invasive lobular carcinomas (ILCs) and IDCs differed from each other in their E-cad expression. None of the ILCs (n=55) retained normal E-cad expression in contrast to 48% (115 of 239) of the IDCs. In 259 primary IDCs, reduced E-cad expression was associated with high histologic grade (chi square test for trend, P < .001), negative estrogen receptor status (ER; Fisher's exact test; P = .042), and marginally with axillary node involvement (Fisher's exact test, P = .063). In a subset of 109 primary IDC patients whose clinical follow-up was available (median follow-up 51 months), reduced E-cad expression was associated with shortened disease-free survival (DFS; Mantel-Cox test, P = .027). In Cox's multivariate regression analysis, progesterone receptor status (P = .018) and E-cad expression (P = .072) were selected as independent predictors of DFS. Our findings provide clinical evidence that loss of normal E-cad expression is an indicator of increased invasiveness and dedifferentiation in breast carcinoma. E-cad is a potentially important prognostic factor in primary IDCs.

Comparison of different immunohistochemical methods in the assessment of angiogenesis: lack of prognostic value in a group of 77 selected node-negative breast carcinomas.

There is evidence that tumor angiogenesis, as detected by immunohistochemical staining of endothelium, is of prognostic significance in breast cancer. However, little attention has been paid to possible differences between antibodies or to quantitation of the stained microvessels. We compared three endothelial cell antibodies [anti-human von Willebrand factor (anti-VWF, also termed factor VIII), anti-CD31, and anti-CD34] in archival paraffin-embedded specimens. Anti-CD34 and anti-VWF showed better staining performances than anti-CD31, although the staining results with different antibodies were comparable. Two different methods of microvessel quantitation (the highest microvessel count and percentage microvessel area) were evaluated and also showed significant correlation. From a retrospective database (n = 1000), 77 axillary node-negative invasive ductal breast carcinomas were selected on the basis of clinical outcome to maximize the prognostic power of the sample set (37 died due to a metastatic breast carcinoma, 40 showed no recurrence during 8-yr follow-up). Microvessel quantitations were related to flow cytometric DNA ploidy, c-erb-B-2 overexpression, and estrogen receptor status of the tumor. Surprisingly, neither highest microvessel counts nor microvessel area measurements quantitated with anti-CD34 or anti-VWF immunohistochemistry were able to discriminate between favorable and unfavorable outcome patients. Thus, our results suggest that further evidence is still needed on tumor angiogenesis immunohistochemistry before it can be adopted as a prognostic marker in routine, clinical practice.

Prognostic value of cells with more than 5c DNA content in node-negative breast cancer as determined by image cytometry from tissue sections.

The aim of this investigation was to study the prognostic significance of 5c cells (presence of cancer cells with > 5c DNA content; ie, over 18 pg of DNA per nucleus) in axillary node-negative breast cancer. Tissue sections (3 microns) from 134 tumors were stained for DNA using the Feulgen method and screened for the percentage of 5c cells with the CAS 200 image analysis system (Cell Analysis System, Inc, Lombard, IL). Cancer cells with a DNA content exceeding the 5c level were found in 45% (60 of 134) of the cases, accounting for a median of 0.2% (range, 0.05% to 1.05%) of all cells. The presence of 5c cells was associated with a high histologic grade of the tumor (P = .0001), a large number of mitoses (P < .0001), flow cytometric DNA aneuploidy and high S-phase fraction (P = .0002 and P < .0001, respectively), and c-erbB-2 oncoprotein and p53 tumor suppressor gene product overexpression (P = .0002 and P = .0006, respectively). Patients with 5c cell-positive tumors had a significantly worse 8-year survival rate (P = .003) than those with 5c cell-negative tumors. Subgroup analysis showed that the presence of 5c cells had a prognostic impact in low malignancy tumors, ie, in well-differentiated (grade I or II) and slowly proliferating tumors. Our findings suggest that determination of 5c cells may be a useful additional prognostic factor in axillary node-negative breast cancer. It adds prognostic information, especially in cases that are otherwise thought to have a favorable course.

Proliferating cell nuclear antigen immunohistochemistry using monoclonal antibody 19A2 and a new antigen retrieval technique has prognostic impact in archival paraffin-embedded node-negative breast cancer.

We evaluated whether proliferating cell nuclear antigen (PCNA) immunohistochemistry with antigen retrieval could be used as a measure of cell proliferation in archival, formalin-fixed, paraffin-embedded tissues and whether the staining results have long-term prognostic significance in axillary node-negative breast cancer. Primary tumor samples obtained from 109 axillary-node-negative breast cancer cases were used for the study. The best staining results were obtained with the 19A2 antibody after microwave heating in a solution of saturated lead thiocyanate. Using this method, there was a significant correlation (linear regression, r = 0.580, P < 0.001) between the proportion of PCNA19A2-positive carcinoma cells (PCNA19A2 score) and DNA flow cytometric S phase fraction. A high PCNA19A2 score was associated with high mitotic count, DNA aneuploidy, and absence of estrogen receptors. Axillary-node-negative patients with a high PCNA19A2 score (cut-point 8%) had significantly worse prognosis than those with a low PCNA19A2 score (P = 0.008). According to a Cox multivariate analysis, PCNA19A2 score had independent prognostic value but only if S phase fraction was excluded from the analysis. In our study, the PCNAPC10 score correlated weakly only with primary tumor size (analysis of variance) and prognosis (5-year univariate survival analysis), but the significance of these findings needs further evaluation. In conclusion, PCNA immunohistochemistry with the 19A2 antibody after an appropriate antigen retrieval treatment may offer a useful alternative to DNA flow cytometry for the analysis of cell proliferation activity from formalin-fixed, paraffin-embedded breast carcinomas.

Intratumor variation in cell proliferation in breast carcinoma as determined by antiproliferating cell nuclear antigen monoclonal antibody and automated image analysis.

Immunohistochemical detection of the proliferating cell nuclear antigen (PCNA) represents a potentially useful tool for the study of tumor proliferative activity. To study the intratumor heterogeneity of tumor growth, 88 breast carcinomas were immunostained with the anti-PCNA antibody 19F4 and analyzed with the CAS 200 image analysis system (Cell Analysis System, Inc., Lombard, IL). For each sample, 12 fields from both the central and the peripheral areas of the tumor were measured. The proportion of PCNA-positive nuclear area in the whole tumor (PCNAt score) varied from 0.7% to 45.2% (median, 14.4%). There was considerable intratumor heterogeneity in the staining for PCNA. In 79% of the specimens, the PCNA score was higher in peripheral areas than in the center of the tumor, the average difference being +3.4% (range, -9.2- +15.1%; P < 0.0001, Student's t-test). The S-phase fraction, determined by DNA flow cytometry of the same tumors, varied from 2.0% to 32.6% (median, 10.0%). The PCNA score showed a significant correlation with the S-phase fraction (r = 0.469, P < 0.001). Most divergent results were those with high PCNA scores and low S-phase fraction; possible explanations for this are discussed. The PCNA score also was related to the histologic grade of the tumors (P = 0.03, analysis of variance). In conclusion, proliferation indices obtained from different areas of a tumor can differ significantly because of intratumor heterogeneity in growth fractions. The PCNA immunostaining correlates with well-known prognostic factors (S-phase fraction and histologic tumor grade) in breast carcinoma.