<p>Primary cutaneous large B-cell lymphoma, leg type has been individualized from nodal diffuse large B-cell lymphoma. The objective of this study was to screen primary cutaneous large B-cell lymphoma, leg type for genetic alterations recently described in nodal diffuse large B-cell lymphoma. Skin biopsies from 23 patients were analyzed for IRF4, BCL2, BCL6, and MYC expression. FISH testing was performed for BCL2, BCL6, MYC with separation probes and for CDKN2A and PRDM1/BLIMP1 deletion. Multiple sequential FISH analyses with up to six probes were performed to define samples with multiple cytogenetic alterations. MYD88 mutations were studied by Sanger sequencing. All cases but one displayed at least one genetic alteration (96%). Nine patients exhibited a single genetic mutation and 12 combined several alterations (52%). We observed a split for BCL2, BCL6, or MYC in 1/23, 6/23, and 3/23 of cases, respectively. No double-hit lymphoma was observed. CDKN2A deletion was detected by FISH in only 5/23 cases. BLIMP1 and/or 6q deletion was observed at a higher rate in 10/20 of cases. No correlation between rearrangement and immunohistochemical expression was found for BCL2 or MYC. FISH tracking of sequential hybridizations showed that several alterations were carried by the same nuclei. The p.L265P MYD88 mutation was found in 11/18 (61%) of cases. Contrary to most cutaneous lymphomas that rarely harbor primary genetic alteration of their nodal histological equivalent, primary cutaneous large B-cell lymphoma, leg type seems to be a 'cutaneous counterpart' of activated B-cell-like diffuse large B-cell lymphoma with a similar cytogenetic profile and a high rate of MYD88 oncogenic L265P mutation. This also suggests a common lymphomagenesis with NF-jB activation, strong IRF4 expression and terminal B-cell differentiation blockage. Our data support the use of therapies targeting NF-jB, as most patients displayed disease progression and resistance to conventional therapies.</p>

Genetic and biochemical sperm integrity is essential to ensure the reproductive competence. However, spermatogenesis involves physiological changes that could endanger sperm integrity. DNA protamination and apoptosis have been studied extensively. Furthermore, elevated rates of aneuploidy and DNA injury correlate with reproductive failures. Consequently, this study applied the conventional spermiogram method in combination with molecular tests to assess genetic integrity in ejaculate from normozoospermic patients with implantation failure by retrospectively analysing aneuploidy (chromosomes 18, X, Y), DNA fragmentation, externalization of phosphatidylserine and mitochondrial membrane potential status before and after magnetic activated cell sorting (MACS). Aneuploid, apoptotic and DNA-injured spermatozoa decreased significantly after MACS. A positive correlation was detected between reduction of aneuploidy and decreased DNA damage, but no correlation was determined with apoptotic markers. The interactions between apoptotic markers, DNA integrity and aneuploidy, and the effect of MACS on these parameters, remain unknown. In conclusion, use of MACS reduced aneuploidy, DNA fragmentation and apoptosis. A postulated mechanism relating aneuploidy and DNA injury is discussed; on the contrary, cell death markers could not be related. An 'apoptotic-like' route could explain this situation. Genetic and biochemical sperm integrity is essential to ensure reproductive success and support the earliest phases of embryo development. Paradoxically, spermatogenesis involves physiological changes that could endanger the DNA and cell integrity. Sperm-specific mechanisms have been studied extensively, and DNA packaging and programmed cell death (apoptosis) are potentially harmful. Also, elevated rates of chromosomal numerical abnormalities and breakage of sperm DNA have been correlated with reproductive failures. In this context, basic sperm examination methods have been combined with molecular tests to assess genetic integrity. On the other hand, magnetic activated cell sorting (MACS) can reduce the number of programmed-to-death spermatozoa. This system retains damaged spermatozoa, thereby improving the sample's quality. The relationships between apoptosis, DNA integrity and chromosomal abnormalities (aneuploidy) as a whole, and the effect of MACS on these parameters remain unknown. We analysed aneuploidy, DNA damage, and biochemical markers of cell death in ejaculate from normozoospermic patients with implantation failures before and after MACS. Aneuploid, apoptotic and DNA-injured spermatozoa decreased significantly after MACS. A positive correlation was detected between the reduction of aneuploidy and DNA damage; on the contrary, no correlation was determined with apoptotic markers. In conclusion, the use of MACS reduced aneuploidy, DNA breakages and apoptosis. A hypothesized mechanism relating aneuploidy and DNA injury is discussed; on the contrary, death cell markers could not be directly related. An 'apoptotic-like' route could explain this situation.

<p>In the April 2013 issue of Haematologica, Lee <em>et al.</em> have described the <em>TET1</em> genomic breakpoints and clinical features of <em>MLL-TET1</em> rearranged cases of acute leukemia. So far, 13 cases have been reported in the literature, 11 in acute myeloid leukemia (AML) patients and 2 in B-cell precursor acute lymphoblastic leukemia (ALL). It was also recently reported that <em>MLL</em> is fused to <em>TET1</em> in only 5 out of 1,590 <em>MLL</em> rearranged <em>AML</em> cases (0.3%). Although those cases are very uncommon, their study can improve our current understanding of leukemogenesis. We report here the first t(10;11) <em>MLL-TET1</em> positive case of T-cell lymphoblastic lymphoma occurring in a 31-year old male patient, with a subsequent transformation to AML.</p> <p>The patient was referred for a large mediastinal mass and right pleural effusion. Blood cell count showed no abnormalities. Mediastinal and bronchus biopsies led to the diagnosis of a precursor-T-cell lymphoblastic lymphoma (pre-T LBL), expressing CD3, CD5, CD4, CD8 and CD10 antigens, together with a high expression of Ki67 (90%). No expression of CD34 or CD79a was observed. The same cells were observed in pleural fluid that expressed CD3, CD4, CD8, CD2, CD7, CD10 antigens but neither CD34 nor myeloperoxidase. Bone marrow examination and central nervous system imaging did not show any other specific localization. The patient was treated following the Groupe d’Etudes des Lymphomes de l’Adulte (GELA) LL03 protocol, and was considered in complete remission after induction and consolidation phases. A 32×22×48 mm residual mediastinal mass remained after treatment, without hypermetabolic abnormality on the FDG-PET scan and was considered to be fibronecrotic scar tissue. Fourteen months after the diagnosis, during the maintenance therapy, a bone marrow examination was performed for thrombopenia (6 g/L) that revealed a myelomonocytic acute leukemia with trilineage dysplasia. The mediastinal mass remained unchanged on the imaging scan. The patient achieved complete remission after intensive chemotherapy based on cytarabine and daunorubicin, followed by a consolidation course with high-dose cytarabine. A non-familial donor allogeneic bone marrow transplant (10/10 match) was performed four months after the diagnosis of the acute myeloid leukemia that was complicated by a Grade IV acute graft-<em>versus</em>-host disease involving digestive tract, liver and skin. The patient died 54 days after the transplant of bacterial sepsis leading to multi-organ failure.</p>

The study design and obtained results represent an intercomparison of various laboratories performing dose assessment using the dicentric chromosome analysis (DCA) as a diagnostic triage tool for individual radiation dose assessment. Homogenously X-irradiated (240 kVp, 1 Gy/min) blood samples for establishing calibration data (0.25-5 Gy) as well as blind samples (0.1-6.4 Gy) were sent to the participants. DCA was performed according to established protocols. The time taken to report dose estimates was documented for each laboratory. Additional information concerning laboratory organization/characteristics as well as assay performance was collected. The mean absolute difference (MAD) was calculated and radiation doses were merged into four triage categories reflecting clinical aspects to calculate accuracy, sensitivity and specificity. The earliest report time was 2.4 days after sample arrival. DCA dose estimates were reported with high and comparable accuracy, with MAD values ranging between 0.16-0.5 Gy for both manual and automated scoring. No significant differences were found for dose estimates based either on 20, 30, 40 or 50 cells, suggesting that the scored number of cells can be reduced from 50 to 20 without loss of precision of triage dose estimates, at least for homogenous exposure scenarios. Triage categories of clinical significance could be discriminated efficiently using both scoring procedures.

Mass casualty scenarios of radiation exposure require high throughput biological dosimetry techniques for population triage in order to rapidly identify individuals who require clinical treatment. The manual dicentric assay is a highly suitable technique, but it is also very time consuming and requires well trained scorers. In the framework of the MULTIBIODOSE EU FP7 project, semi-automated dicentric scoring has been established in six European biodosimetry laboratories. Whole blood was irradiated with a Co-60 gamma source resulting in 8 different doses between 0 and 4.5Gy and then shipped to the six participating laboratories. To investigate two different scoring strategies, cell cultures were set up with short term (2-3h) or long term (24h) colcemid treatment. Three classifiers for automatic dicentric detection were applied, two of which were developed specifically for these two different culture techniques. The automation procedure included metaphase finding, capture of cells at high resolution and detection of dicentric candidates. The automatically detected dicentric candidates were then evaluated by a trained human scorer, which led to the term 'semi-automated' being applied to the analysis. The six participating laboratories established at least one semi-automated calibration curve each, using the appropriate classifier for their colcemid treatment time. There was no significant difference between the calibration curves established, regardless of the classifier used. The ratio of false positive to true positive dicentric candidates was dose dependent. The total staff effort required for analysing 150 metaphases using the semi-automated approach was 2min as opposed to 60min for manual scoring of 50 metaphases. Semi-automated dicentric scoring is a useful tool in a large scale radiation accident as it enables high throughput screening of samples for fast triage of potentially exposed individuals. Furthermore, the results from the participating laboratories were comparable which supports networking between laboratories for this assay.

In this study, we compared conventional sperm selection with high-magnification morphology based on the motile sperm organellar morphology examination (MSOME) criteria, and hyaluronic acid (HA) binding for sperm chromosome aneuploidy and DNA fragmentation rates. Semen from 50 severe male factor cases was processed through density gradient centrifugation, and subjected to sperm selection by using the conventional method (control), high magnification at ?6650 or HA binding. Aneuploidy was detected by fluorescence in situ hybridization with probes for chromosomes 13, 18, 21, X and Y, and DNA fragmentation by the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) method. Spermatozoa selected under high-magnification had a lower DNA fragmentation rate (2.6\% vs. 1.7\%; P=0.032), with no significant difference in aneuploidy rate (0.8\% vs 0.7\%; P=0.583), than those selected by the HA binding method. Spermatozoa selected by both methods had much lower aneuploidy and DNA fragmentation rate than the controls (7\% aneuploidy and 26.8\% DNA fragmentation rates, respectively). In the high-magnification group, the aneuploidy rate was lower when the best spermatozoa were selected than when only the second-best spermatozoa were available for selection, but the DNA fragmentation rate was not different. In conclusion, sperm selection under high magnification was more effective than under HA binding in selecting spermatozoa with low DNA fragmentation rate, but the small difference (0.9\%) might not be clinically meaningful. Both methods were better than the conventional method of sperm selection.

<p>Background Approximately 1% of the spermatozoa found in ejaculate of healthy men are aneuploid and this rate increases in the population of subfertile and infertile men. Moreover, fertilization with these aneuploid sperm can lead to impaired embryo development. Fluorescent In Situ Hybridization (FISH) is the common cytogenetic tool used for aneuploidy screening on sperm. However, it is a time-consuming technique and cytogenetic or in vitro fertilization laboratories cannot routinely use it and face the increasing demand of such analyses before Assisted Reproductive Techniques (ART). As automation can be a clue for routine practice, this study compares manual and automated scoring of sperm aneuploidy rates using a Metafer MetaSystems device. The results obtained also contribute to global data about FISH on sperm cells. Methods We recruited 100 men addressed for sperm cryopreservation. They all signed an informed consent to participate in the study. 29 men were donors or consulted before vasectomy (control group) and 71 were suffering of Hodgkin’s disease or non Hodgkin lymphoma (patient group). One semen sample was collected for each patient, analyzed according to WHO criteria and prepared for a triple-color FISH using centromeric probes for chromosomes 18, X and Y. Automated scoring was performed using a Metafer MetaSystems device. Results 507,019 cells were scored. We found a strong concordance between the automated and the manual reading (d  &lt; 0.01 in Bland-Altman test). We also did not find a statistically significant difference between the automated and the manual reading using Wilcoxon test for total aneuploidy rate (p = 0.06), sex chromosomes disomy (p = 0.33), chromosome 18 disomy (p = 0.39) and diploidy (p = 0.21). Cumulative rate of total aneuploidy was 0.78% ± 0.212% for patient group and 0.54% ± 0.15 for control group and among this, sex chromosome XY disomy rate was of 0.54% for patient group and 0.27% for control group. This study validates the automated reading for FISH on sperm with a Metafer Metasystems® device and allows its use in a laboratory routine.</p>

Although somatic homologous pairing is common in Drosophila it is not generally observed in mammalian cells. However, a number of regions have recently been shown to come into close proximity with their homologous allele, and it has been proposed that pairing might be involved in the establishment or maintenance of monoallelic expression. Here, we investigate the pairing properties of various imprinted and non-imprinted regions in mouse tissues and ES cells. We find by allele-specific 4C-Seq and DNA FISH that the Kcnq1 imprinted region displays frequent pairing but that this is not dependent on monoallelic expression. We demonstrate that pairing involves larger chromosomal regions and that the two chromosome territories come close together. Frequent pairing is not associated with imprinted status or DNA repair, but is influenced by chromosomal location and transcription. We propose that homologous pairing is not exclusive to specialised regions or specific functional events, and speculate that it provides the cell with the opportunity of trans-allelic effects on gene regulation.

<p>Bone marrow specimens from 185 patients with plasma cell disorders (PCD) were investigated by fluorescence in situ hybridization (FISH) in order to determine the temporal sequence of cytogenetic aberrations. In 25 cases combined FISH analysis has also been performed at single cell level. Clonal evolution was observed in 16% of cases. The Δ13 was preceded by t(4;14)(p16;q32) and t(14;16)(q32;q23) translocations. Deletion of p53 gene was a secondary aberration compared to Δ13 and t(11;14)(q13;q32) translocation. In 22% of all cases with recurrent IGH translocation, this aberration was presented only in a subset of purified plasma cells questioning its initiating role.</p>

<p>Urovysion multitarget fluorescence in situ hybridization (FISH) assay is a promising tool for detection of bladder cancer, however, there is still no consensus regarding abnormal signal pattern and cut-off level, and the recommended targeting carries limitations similar to urine cytology. Aim of this study was to explore diagnostic benefits of a recently introduced method featuring target specific genotyping, as well as to investigate the feasibility of locally and statistically determined cut-off, compared with conventional evaluation scheme. Histology, cytology, and comparative FISH approaches were performed on 42 patients with high clinical suspicion for urothelial carcinoma (UC). FISH parallels were (1) Urovysion-alone (according to manufacturer's instruction); (2) Targeted-Urovysion (cytokeratin7 immunophenotyping followed by Urovysion), both of which evaluated by both conventional and statistical evaluation scheme. For statistical evaluation cut-offs and sufficient sample size were determined on controls and ratio of positive cells was recorded, whereas conventional evaluation relied on manufacturer's recommendations. The specificity of cytology, Urovysion-alone in general and targeted-Urovysion in general appeared 86%, 86%, and 100%, respectively. In the same comparison, overall sensitivity was 60%, 80%, and 93%, respectively. In superficial cases sensitivity was 48% for cytology, 72% for Urovysion-alone and 91% for targeted-Urovysion, while no prominent differences were seen in muscle invasive cases. The ratio of FISH positive cells was proportionate with both stage and grade, however, targeted genotyping could separate high grade/high stage cases more effectively. In conclusion, CK7 targeting raises diagnostic efficiency of Urovysion, and could be an ideal tool for identifying tumor cells in ambiguous cases or when other tumors are present. Statistical evaluation produces accuracy comparable with results of conventional evaluation, and with laboratories setting cut-offs individually but according harmonized protocol, it could aid method standardization. Furthermore, by providing additional quantitative information about tumor characteristics, is likely to have therapy relevant value in the future.</p>

Albeit genetically highly heterogeneous, muscular dystrophies (MDs) share a convergent pathology leading to muscle wasting accompanied by proliferation of fibrous and fatty tissue, suggesting a common MD-pathomechanism. Here we show that mutations in muscular dystrophy genes (Dmd, Dysf, Capn3, Large) lead to the spontaneous formation of skeletal muscle-derived malignant tumors in mice, presenting as mixed rhabdomyo-, fibro-, and liposarcomas. Primary MD-gene defects and strain background strongly influence sarcoma incidence, latency, localization, and gender prevalence. Combined loss of dystrophin and dysferlin, as well as dystrophin and calpain-3, leads to accelerated tumor formation. Irrespective of the primary gene defects, all MD sarcomas share non-random genomic alterations including frequent losses of tumor suppressors (Cdkn2a, Nf1), amplification of oncogenes (Met, Jun), recurrent duplications of whole chromosomes 8 and 15, and DNA damage. Remarkably, these sarcoma-specific genetic lesions are already regularly present in skeletal muscles in aged MD mice even prior to sarcoma development. Accordingly, we show also that skeletal muscle from human muscular dystrophy patients is affected by gross genomic instability, represented by DNA double-strand breaks and age-related accumulation of aneusomies. These novel aspects of molecular pathologies common to muscular dystrophies and tumor biology will potentially influence the strategies to combat these diseases.

<p>The accuracy of melanoma diagnosis continues to challenge the pathology community, even today with sophisticated histopathologic techniques. Melanocytic lesions exhibit significant morphological heterogeneity. While the majority of biopsies can be classified as benign (nevus) or malignant (melanoma) using well-established histopathologic criteria, there exists a cohort for which the prediction of clinical behaviour and invasive or metastatic potential is difficult if not impossible to ascertain on the basis of morphological features alone. Multiple studies have shown that there is significant disagreement between pathologists and even expert dermatopathologists in the diagnosis of this subgroup of difficult melanocytic lesions.A four probe FISH assay was utilized to analyse a cohort of 500 samples including 157 nevus, 176 dysplastic nevus and 167 melanoma specimens. Review of the lesions determined the assay identified genetic abnormalities in a total of 83.8% of melanomas, and 1.9% of nevus without atypia, while genetic abnormalities were identified in 6.3%, 6.7%, and 10.3% of nevus identified with mild, moderate and severe atypia, respectively.Based on this study, inheritable genetic damage/instability identified by FISH testing is a hallmark of a progressive malignant process, and a valuable diagnostic tool for the identification of high risk lesions.</p>

<p>Although aneuploidy has many possible causes, it often results from underlying chromosomal instability (CIN) leading to an unstable karyotype with cell-to-cell variation and multiple subclones. To test for the presence of CIN in high hyperdiploid acute lymphoblastic leukemia (HeH ALL) at diagnosis, we investigated 20 patients (10 HeH ALL and 10 non-HeH ALL), using automated four-color interphase fluorescence in situ hybridization (I-FISH) with centromeric probes for chromosomes 4, 6, 10, and 17. In HeH ALL, the proportion of abnormal cells ranged from 36.3% to 92.4%, and a variety of aneuploid populations were identified. Compared with conventional cytogenetics, I-FISH revealed numerous additional clones, some of them very small. To investigate the nature and origin of this clonal heterogeneity, we determined average numerical CIN values for all four chromosomes together and for each chromosome and patient group. The CIN values in HeH ALL were relatively high (range, 22.2-44.7%), compared with those in non-HeH ALL (3.2-6.4\), thus accounting for the presence of numerical CIN in HeH ALL at diagnosis. We conclude that numerical CIN may be at the origin of the high level of clonal heterogeneity revealed by I-FISH in HeH ALL at presentation, which would corroborate the potential role of CIN in tumor pathogenesis.</p>

A 12-year-old male with pre-B-cell acute lymphoblastic leukemia with cryptic BCR/ABL rearrangement underwent sex-mismatched allogeneic bone marrow transplantation (allo-BMT). Contradictory results were provided by various chimerism analyses 3 months later. Y-chromosome-specific quantitative polymerase chain reaction and sex chromosome-specific interphase fluorescence in situ hybridization (i-FISH) showed complete donor chimerism. Analysis of autosomal short tandem repeats (A-STR), BCR/ABL i-FISH test, and X-STR haplotype indicated relapse. Metaphase-FISH and combined BCR/ABL and sex chromosome-specific i-FISH patterns revealed loss of the Y-chromosome and duplication of the X-chromosome in the host cells. Sex chromosome changes after allo-BMT can cause significant difficulties in chimerism analysis.

<p>DNA-, RNA-, and cell-based methods provide different biologic information for determining the presence of minimal residual disease (MRD). We monitored the responses of patients with pediatric acute lymphoblastic leukemia (pALL) using DNA markers, TEL/AML1 expression, and scanning fluorescence microscopy (SFM). Using SFM, 36% of patients exhibited 1.5-3.1 log and 2.9-4.2 log higher MRD levels compared with those based on DNA and RNA markers, respectively. CD10+ ancestor cells with germline antigen receptors, but silent TEL/AML1 expression, may reside in the lymphoid stem cell compartment of treated t(12;21)-positive patients and might act as a potential source of cells for late relapses.</p>

Dorsal root ganglia (DRG)-neurons are commonly characterized immunocytochemically. Cells are mostly grouped by the experimenter's eye as #marker-positive# and #marker-negative# according to their immunofluorescence intensity. Classification criteria remain largely undefined. Overcoming this shortfall, we established a quantitative automated microscopy (QuAM) for a defined and multiparametric analysis of adherent heterogeneous primary neurons on a single cell base.The growth factors NGF, GDNF and EGF activate the MAP-kinase Erk1/2 via receptor tyrosine kinase signalling. NGF and GDNF are established factors in regeneration and sensitization of nociceptive neurons. If also the tissue regenerating growth factor, EGF, influences nociceptors is so far unknown. We asked, if EGF can act on nociceptors, and if QuAM can elucidate differences between NGF, GDNF and EGF induced Erk1/2 activation kinetics. Finally, we evaluated, if the investigation of one signalling component allows prediction of the behavioral response to a reagent not tested on nociceptors such as EGF.We established a software-based neuron identification, described quantitatively DRG-neuron heterogeneity and correlated measured sample sizes and corresponding assay sensitivity. Analysing more than 70,000 individual neurons we defined neuronal subgroups based on differential Erk1/2 activation status in sensory neurons. Baseline activity levels varied strongly already in untreated neurons. NGF and GDNF subgroup responsiveness correlated with their subgroup specificity on IB4(+)- and IB4(-)-neurons, respectively. We confirmed expression of EGF-receptors in all sensory neurons. EGF treatment induced STAT3 translocation into the nucleus. Nevertheless, we could not detect any EGF induced Erk1/2 phosphorylation. Accordingly, intradermal injection of EGF resulted in a fundamentally different outcome than NGF/GDNF. EGF did not induce mechanical hyperalgesia, but blocked PGE2-induced sensitization.QuAM is a suitable if not necessary tool to analyze activation of endogenous signalling in heterogeneous cultures. NGF, GDNF and EGF stimulation of DRG-neurons shows differential Erk1/2 activation responses and a corresponding differential behavioral phenotype. Thus, in addition to expression-markers also signalling-activity can be taken for functional subgroup differentiation and as predictor of behavioral outcome. The anti-nociceptive function of EGF is an intriguing result in the context of tissue damage but also for understanding pain resulting from EGF-receptor block during cancer therapy.

<p>The simultaneous detection of protein expression and gene copy number changes in patient samples, like paraffin-embedded tissue sections, is challenging since the procedures of immunohistochemistry (IHC) and Fluorescence in situ Hybridization (FISH) negatively influence each other which often results in suboptimal staining. Therefore, we developed a novel automated algorithm based on relocation which allows subsequent detection of protein content and gene copy number changes within the same cell. Paraffin-embedded tissue sections of colorectal cancers were stained for CD133 expression. IHC images were acquired and image coordinates recorded. Slides were subsequently hybridized with fluorescently labeled DNA probes. FISH images were taken at the previously recorded positions allowing for direct comparison of protein expression and gene copy number signals within the same cells/tissue areas. Relocation, acquisition of the IHC and FISH images, and enumeration of FISH signals in the immunophenotyped tumour areas were done in an automated fashion. Automated FISH analysis was performed on 13 different colon cancer samples that had been stained for CD133; each sample was scored for MYC, ZNF217 and Chromosome 6 in CD133 positive and negative glands. From the 13 cases four (31%) showed amplification for the MYC oncogene and seven of 13 (54%) cases were amplified for ZNF217. There was no significant difference between CD133 positive tumour and CD133 negative tumour cells. The technique and algorithm presented here enables an easy and reproducible combination of IHC and FISH based on a novel automated algorithm using relocation and automated spot counting.</p>

<p>Gene fusions play a critical role in cancer progression. The mechanisms underlying their genesis and cell type specificity are not well understood. About 50% of human prostate cancers display a gene fusion involving the 5' untranslated region of TMPRSS2, an androgen-regulated gene, and the protein-coding sequences of ERG, which encodes an ETS transcription factor. Studying human prostate cancer cells by fluorescence in situ hybridization, we show that androgen signaling induces proximity of the TMPRSS2 and ERG genomic loci, both located on chromosome 21q22.2. Subsequent exposure of the cells to gamma-irradiation, which causes DNA double strand breaks, facilitates the formation of the TMPRSS2-ERG gene fusion. These results may help explain why TMPRSS2-ERG fusions are restricted to the prostate, which is dependent on androgen signaling.</p>

<p>Gene expression profiling of breast cancer has identified two biologically distinct estrogen receptor (ER)-positive subtypes of breast cancer: luminal A and luminal B. Luminal B tumors have higher proliferation and poorer prognosis than luminal A tumors. In this study, we developed a clinically practical immunohistochemistry assay to distinguish luminal B from luminal A tumors and investigated its ability to separate tumors according to breast cancer recurrence-free and disease-specific survival.Tumors from a cohort of 357 patients with invasive breast carcinomas were subtyped by gene expression profile. Hormone receptor status, HER2 status, and the Ki67 index (percentage of Ki67-positive cancer nuclei) were determined immunohistochemically. Receiver operating characteristic curves were used to determine the Ki67 cut point to distinguish luminal B from luminal A tumors. The prognostic value of the immunohistochemical assignment for breast cancer recurrence-free and disease-specific survival was investigated with an independent tissue microarray series of 4046 breast cancers by use of Kaplan-Meier curves and multivariable Cox regression.Gene expression profiling classified 101 (28%) of the 357 tumors as luminal A and 69 (19%) as luminal B. The best Ki67 index cut point to distinguish luminal B from luminal A tumors was 13.25%. In an independent cohort of 4046 patients with breast cancer, 2847 had hormone receptor-positive tumors. When HER2 immunohistochemistry and the Ki67 index were used to subtype these 2847 tumors, we classified 1530 (59%, 95% confidence interval [CI] = 57% to 61%) as luminal A, 846 (33%, 95% CI = 31% to 34%) as luminal B, and 222 (9%, 95% CI = 7% to 10%) as luminal-HER2 positive. Luminal B and luminal-HER2-positive breast cancers were statistically significantly associated with poor breast cancer recurrence-free and disease-specific survival in all adjuvant systemic treatment categories. Of particular relevance are women who received tamoxifen as their sole adjuvant systemic therapy, among whom the 10-year breast cancer-specific survival was 79% (95% CI = 76% to 83%) for luminal A, 64% (95% CI = 59% to 70%) for luminal B, and 57% (95% CI = 47% to 69%) for luminal-HER2 subtypes.Expression of ER, progesterone receptor, and HER2 proteins and the Ki67 index appear to distinguish luminal A from luminal B breast cancer subtypes.</p>