Routine acid decalcification of bone marrow samples can preserve DNA for FISH and CGH studies in metastatic prostate cancer

Effects of fixation and demineralization on histomorphology and DNA amplification of canine bone marrow

Fixation and demineralization protocols for bone marrow (BM) across diagnostic laboratories are not standardized. How different protocols affect histomorphology and DNA amplification is incompletely understood. In this study, 2 fixatives and 3 demineralization methods were tested on canine BM samples. Twenty replicate sternal samples obtained within 24 hours of death were fixed overnight in either acetic acid-zinc-formalin (AZF) or 10% neutral-buffered formalin (NBF) and demineralized with formic acid for 12 hours. Another 53 samples were fixed in AZF and demineralized with hydrochloric acid for 1-hour, formic acid for 12 hours, or ethylenediamine tetraacetic acid (EDTA) for 24 hours. Histologic sections were scored by 4 raters as of insufficient, marginal, good, or excellent quality. In addition, DNA samples extracted from sections treated with the different fixation and demineralization methods were amplified with 3 sets of primers to conserved regions of T cell receptor gamma and immunoglobulin heavy chain genes. Amplification efficiency was graded based on review of capillary electrophoretograms. There was no significant difference in the histomorphology scores of sections fixed in AZF or NBF. However, EDTA-based demineralization yielded higher histomorphology scores than demineralization with hydrochloric or formic acid, whereas formic acid resulted in higher scores than hydrochloric acid. Demineralization with EDTA yielded DNA amplification in 29 of 36 (81%) samples, whereas demineralization with either acid yielded amplification in only 2 of 72 (3%) samples. Although slightly more time-consuming and labor-intensive, tissue demineralization with EDTA results in superior morphology and is critical for polymerase chain reaction (PCR) amplification with the DNA extraction method described in this article.

[Assessment of HER2 status of carcinomas of various localizations]

A detailed description of the methodological aspects of the evaluation of HER2-status in carcinomas of such localizations as the mammary gland, pancreas, salivary glands, stomach, colon, endometrium, bladder, lungs is presented. Approaches and criteria for assessing HER2 status from methodological and clinical points of view are analyzed. The data are systematized in tables for use in practical diagnostic work.

A review of the current understanding of burned bone as a source of DNA for human identification

Identification of incinerated human remains may rely on genetic analysis of burned bone which can prove far more challenging than fresh tissues. Severe thermal insult results in the destruction or denaturation of DNA in soft tissues, however genetic material may be preserved in the skeletal tissues. Considerations for DNA retrieval from these samples include low levels of exogenous DNA, the dense, mineralised nature of bone, and the presence of contamination, and qPCR inhibitors. This review collates current knowledge in three areas relating to optimising DNA recovery from burned bone: 1) impact of burning on bone and subsequent effects on sample collection, 2) difficulties of preparing burned samples for DNA extraction, and 3) protocols for bone decalcification and DNA extraction. Bone decalcification and various DNA extraction protocols have been tested and optimised for ancient bone, suggesting that prolonged EDTA (Ethylenediaminetetraacetic acid) demineralisation followed by solid-phased silica-based extraction techniques provide the greatest DNA yield. However, there is significantly less literature exploring the optimal protocol for incinerated bones. Although burned bone, like ancient and diagenetic bone, can be considered "low-copy", the taphonomic processes occurring are likely different. As techniques developed for ancient samples are tailored to deal with bone that has been altered in a particular way, it is important to understand if burned bone undergoes similar or different changes. Currently the effects of burning on bone and the DNA within it is not fully understood. Future research should focus on increasing our understanding of the effects of heat on bone and on comparing the outcome of various DNA extraction protocols for these tissues.

Highly efficient and automated extraction of DNA from human remains using a modified EZ1 protocol

Bones and teeth often represent the only sources of DNA available for identifying human remains. DNA in bones and teeth is generally better preserved than that in soft tissues because of the presence of hard connective tissue with a high level of calcium. Because of the extensive mineralisation, the choice of an efficient DNA extraction procedure is important to minimise the sampling of a high level of minerals and to remove polymerase chain reaction (PCR) inhibitors. Some protocols are available for DNA extraction from bones and teeth as part of the Qiagen EZ1 DNA Investigator Kit using the EZ1 Advanced XL automated purification platform. To improve the efficiency of DNA extraction from skeletal remains, the present study focuses on a modification to these already available protocols. In this study, different bones and teeth collected between 1 and 50 years after death were subjected to DNA extraction using the standard EZ1 protocol, a supplementary protocol, and a modified protocol. The modified approach included a decalcification step, whereas the Qiagen protocols worked directly on non-decalcified powder. In all three procedures, 150 mg samples were used for DNA extraction. We evaluated the quantity of DNA recovered from samples, the presence of any PCR inhibitors co-extracted, the level of DNA degradation, the quality of short tandem repeat (STR) profiles, and the reproducibility of the modified procedure. When compared with the other protocols, the modified protocol resulted in the best recovery of DNA that was free of PCR inhibitors. Additionally, the STR profiles were reliable and of high quality. In our opinion, the decalcification step increases DNA recovery by softening tissues, which allows lysis solutions to act more effectively. Furthermore, the use of two lysis solutions and the variation added to the EZ1 purification step allow for DNA recovery with quality and quantity superior to those of the previously available Qiagen-based protocols. These findings may be helpful solutions to the problems commonly encountered when dealing with difficult samples, such as bones and teeth.

Key points

Bones and teeth often represent the only sources of DNA for identifying human remains.

The choice of an efficient DNA extraction procedure is important for maximizing DNA recovery and removing PCR inhibitors.

This study focuses on modifications to the previously available Qiagen-based protocols.

The modified protocol enabled the best recovery of DNA, and both quality and quantity were superior to those of the previously available Qiagen-based protocols.

The STR profiles obtained from samples extracted using the modified protocol were reliable and of high quality.

Comparison of bone demineralisation procedures for DNA recovery from burned remains

Recovering DNA from modern incinerated bones can be challenging and may require alteration of routine DNA extraction protocols. It has been postulated that incinerated bones share some similarities with ancient bones, including fragmented DNA, surface contamination and highly mineralised structure, all of which can inhibit the successful recovery of genetic material. For this reason, ancient DNA extraction protocols are often used for incinerated modern samples; however, their effectiveness is still somewhat unclear. Much of this uncertainty exists around the demineralisation step of extraction, specifically the length of incubation and retention or removal of supernatant. As obtaining human samples for forensic research can be challenging, porcine models (Sus scrofa domesticus) are often used as substitutes. This study developed real time PCR assays for porcine nuclear DNA in order to investigate the effects of modified demineralisation protocols on DNA yield from femurs exposed to either short (60 min) or prolonged (120 min) burning. Gradient PCR results indicated 56 °C was the ideal amplification temperature for targeted amplicons, with melt curve analysis showing short and long amplicons corresponded to 80.3 °C and 83 °C peaks respectively. Results of altered extraction protocol showed a trend towards higher DNA yields from longer demineralisation periods however this was not significant. By comparison, retaining supernatant post-demineralisation resulted in significantly greater DNA yields compared to discarding it (P < 0.009). Although DNA content yield decreased with burn duration, the demineralisation treatment variations appeared to have the same effect for all burn lengths. These results suggest that for incinerated modern bone retaining the supernatant following demineralisation can dramatically increase DNA yield.

Influence of decalcification procedures on immunohistochemistry and molecular pathology in breast cancer

Distant breast cancer metastases are nowadays routinely biopsied to reassess receptor status and to isolate DNA for sequencing of druggable targets. Bone metastases are the most frequent subgroup. Decalcification procedures may negatively affect antigenicity and DNA quality. We therefore evaluated the effect of several decalcification procedures on receptor status and DNA/RNA quality. In 23 prospectively collected breast tumors, we compared ERα, PR and HER2 status by immunohistochemistry in (non-decalcified) tissue routinely processed for diagnostic purposes and in parallel tissue decalcified in Christensen's buffer with and without microwave, EDTA and Formical-4. Furthermore, HER2 fluorescence in situ hybridization and DNA/RNA quantity and quality were assessed. We found that the percentage of ERα-positive cells were on average lower in EDTA (P=0.049) and Formical-4 (P=0.047) treated cases, compared with controls, and PR expression showed decreased antigenicity after Christensen's buffer treatment (P=0.041). Overall, a good concordance (weighted kappa) was seen for ERα, PR and HER2 immunohistochemistry when comparing the non-decalcified control tissues with the decalcified tissues. For two patients (9%), there was a potential influence on therapeutic decision making with regard to hormonal therapy or HER2-targeted therapy. HER2 fluorescence in situ hybridization interpretation was seriously hampered by Christensen's buffer and Formical-4, and DNA/RNA quantity and quality were decreased after all four decalcification procedures. Validation on paired primary breast tumor specimens and EDTA-treated bone metastases showed that immunohistochemistry and fluorescence in situ hybridization were well assessable and DNA and RNA yield and quality were sufficient. With this, we conclude that common decalcification procedures have only a modest negative influence on hormone and HER2 receptor immunohistochemistry in breast cancer. However, they may seriously affect DNA/RNA-based diagnostic procedures. Overall, EDTA-based decalcification is therefore to be preferred as it best allows fluorescence in situ hybridization and DNA/RNA isolation.

A Paracrine Role for IL6 in Prostate Cancer Patients: Lack of Production by Primary or Metastatic Tumor Cells

Correlative human studies suggest that the pleiotropic cytokine IL6 contributes to the development and/or progression of prostate cancer. However, the source of IL6 production in the prostate microenvironment in patients has yet to be determined. The cellular origin of IL6 in primary and metastatic prostate cancer was examined in formalin-fixed, paraffin-embedded tissues using a highly sensitive and specific chromogenic in situ hybridization (CISH) assay that underwent extensive analytical validation. Quantitative RT-PCR showed that benign prostate tissues often had higher expression of IL6 mRNA than matched tumor specimens. CISH analysis further indicated that both primary and metastatic prostate adenocarcinoma cells do not express IL6 mRNA. IL6 expression was highly heterogeneous across specimens and was nearly exclusively restricted to the prostate stromal compartment--including endothelial cells and macrophages, among other cell types. The number of IL6-expressing cells correlated positively with the presence of acute inflammation. In metastatic disease, tumor cells were negative in all lesions examined, and IL6 expression was restricted to endothelial cells within the vasculature of bone metastases. Finally, IL6 was not detected in any cells in soft tissue metastases. These data suggest that, in prostate cancer patients, paracrine rather than autocrine IL6 production is likely associated with any role for the cytokine in disease progression.

Biomodification of PCL Scaffolds with Matrigel, HA, and SR1 Enhances De Novo Ectopic Bone Marrow Formation Induced by rhBMP-2

The de novo formation of ectopic bone marrow was induced using 1.2-mm-thin polycaprolactone (PCL) scaffolds biomodified with several different biomaterials. In vivo investigations of de novo bone and bone marrow formation indicated that subcutaneous implantation of PCL scaffolds coated with recombinant human bone morphogenetic protein-2 (rhBMP-2) plus Matrigel, hydroxyapatite (HA), or StemRegenin 1 (SR1) improved formation of bone and hematopoietic bone marrow as determined by microcomputed tomography, and histological and hematopoietic characterizations. Our study provides evidence that thin PCL scaffolds biomodified with Matrigel, HA, and SR1 mimic the environments of real bone and bone marrow, thereby enhancing the de novo ectopic bone marrow formation induced by rhBMP-2. This ectopic bone marrow model will serve as a unique and essential tool for basic research and for clinical applications of postnatal tissue engineering and organ regeneration.

Proposal of an appropriate decalcification method of bone marrow biopsy specimens in the era of expanding genetic molecular study

Background:

The conventional method for decalcification of bone specimens uses hydrochloric acid (HCl) and is notorious for damaging cellular RNA, DNA, and proteins, thus complicating molecular and immunohistochemical analyses. A method that can effectively decalcify while preserving genetic material is necessary.

Methods:

Pairs of bilateral bone marrow biopsies sampled from 53 patients were decalcified according to protocols of two comparison groups: EDTA versus HCl and RDO GOLD (RDO) versus HCl. Pairs of right and left bone marrow biopsy samples harvested from 28 cases were allocated into the EDTA versus HCl comparison group, and 25 cases to the RDO versus HCl comparison group. The decalcification protocols were compared with regards to histomorphology, immunohistochemistry, and molecular analysis. For molecular analysis, we randomly selected 5 cases from the EDTA versus HCl and RDO versus HCl groups.

Results:

The decalcification time for appropriate histomorphologic analysis was the longest in the EDTA method and the shortest in the RDO method. EDTA was superior to RDO or HCl in DNA yield and integrity, assessed via DNA extraction, polymerase chain reaction, and silver in situ hybridization using DNA probes. The EDTA method maintained intact nuclear protein staining on immunohistochemistry, while the HCl method produced poor quality images. Staining after the RDO method had equivocal results. RNA in situ hybridization using kappa and lambda RNA probes measured RNA integrity; the EDTA and RDO method had the best quality, followed by HCl.

Conclusions:

The EDTA protocol would be the best in preserving genetic material. RDO may be an acceptable alternative when rapid decalcification is necessary.

A review of preanalytical factors affecting molecular, protein, and morphological analysis of formalin-fixed, paraffin-embedded (FFPE) tissue: how well do you know your FFPE specimen?

CONTEXT

Formalin fixation and paraffin embedding is a timeless, cost-efficient, and widely adopted method of preserving human tissue biospecimens that has resulted in a substantial reservoir of formalin-fixed, paraffin-embedded blocks that represent both the pathology and preanalytical handling of the biospecimen. This reservoir of specimens is increasingly being used for DNA, RNA, and proteomic analyses.

OBJECTIVE

To evaluate the impact of preanalytical factors associated with the formalin fixation and paraffin embedding process on downstream morphological and molecular endpoints.

DATA SOURCES

We surveyed the existing literature using the National Cancer Institute's Biospecimen Research Database for published reports investigating the potential influence of preanalytical factors associated with the formalin fixation and paraffin embedding process on DNA, RNA, protein, and morphological endpoints.

CONCLUSIONS

Based on the literature evidence, the molecular, proteomic, and morphological endpoints can be altered in formalin-fixed, paraffin-embedded specimens by suboptimal processing conditions. While the direction and magnitude of effects associated with a given preanalytical factor were dependent on the analyte (DNA, RNA, protein, and morphology) and analytical platform, acceptable conditions are highlighted, and a summary of conditions that could preclude analysis is provided.

Mutational profiling of bone metastases from lung adenocarcinoma: results of a prospective study (POUMOS-TEC)

Targeted therapies have improved patient survival in metastatic lung adenocarcinoma. Molecular diagnosis is a key element to identify oncogenic drivers predicting the efficacy of these agents. In stage IV patients, histopathological diagnosis is often performed on bone metastases biopsy, but routine procedure of decalcification may alter DNA quality for subsequent molecular tests. We set up a procedure to perform molecular analyses on bone metastasis and describe the results of mutational profiling. POUMOS-TEC is a prospective study conducted in stage IV lung adenocarcinomas. Bone metastasis specimens from surgery and CT-scan guided biopsies were sent fresh for immediate formalin-fixation. Decalcification was performed, only when necessary, using EDTA. Controls were processed with acid decalcification. DNA extraction was performed after laser microdissection. Mutational profiling of oncogenic drivers was conducted as recommended by the French National Cancer Institute. Diagnosis efficiency of the computed tomography (CT)-scan guided biopsy process was assessed. Among 177 collected bone metastases specimens, 49 came from lung adenocarcinomas. Specimens processed with no decalcification or EDTA (n=45) provided high-quality DNA. Molecular profiling was performed in 44/45 (98%) of cases. The results of the whole panel of oncogenic drivers (EGFR, KRAS, BRAF, PIK3CA, HER2 and ALK) were obtained in 41/45 (91%) of cases. A mutation was observed in 50% of cases including 32% of KRAS and 14% of epidermal growth factor receptor (EGFR) mutations. CT-scan biopsy efficiency rate was 96%. We demonstrated the feasibility to routinely conduct mutational profiling on bone metastases biopsies. We observed a higher rate of EGFR mutations (+42%) in comparison with the average rate of all stage IV lung adenocarcinomas. This procedure is a new step toward the goal of personalized medicine to treat lung cancers and other osteophilic tumors.

Effects of fixation and storage of human tissue samples on nucleic Acid preservation

Background

Because of recent advances in the molecular diagnosis of cancer patients, tissue quality has become more important in daily practice.

Methods

To evaluate the effects of fixative, duration of fixation, decalcification, and storage periods on nucleic acid integrity, DNA and RNA were extracted from gastrointestinal cancer tissue. The yield and purity were analyzed, and polymerase chain reaction (PCR) for glyceraldehyde 3-phosphate dehydrogenase (GAPDH; 60 bp), β-actin (148 bp), and human growth hormone (hGH; 434 bp) and real-time reverse transcription-PCR for β-actin (97 bp) were performed.

Results

All formalin-fixed paraffin-embedded (FFPE) and methacarn-fixed paraffin-embedded (MFPE) samples tested positive for GAPDH and β-actin by PCR. hGH was successfully detected in all MFPE samples, but in only 46.7% of the FFPE samples. Prolonged formalin fixation resulted in fewer GAPDH and β-actin PCR products, and amplification of hGH was not successful. The PCR and reverse transcription-PCR results were significantly affected by the duration of decalcification. The yield, purity, and integrity of mRNA progressively decreased with increased storage periods of paraffin blocks.

Conclusions

Fixation and storage should therefore be standardized in order to improve the quality of molecular pathologic diagnosis.

Analysis of the effect of various decalcification agents on the quantity and quality of nucleic acid (DNA and RNA) recovered from bone biopsies

Molecular studies are part of standard care for cancer patients. Bone, a common and sometimes sole site of metastasis, requires decalcification for morphological examination. Many commonly used decalcification agents contain strong acids that degrade nucleic acids. The paradigm shift in oncology, with biomarker targeted therapy and gene expression profiling analysis, requires sufficient nucleic acid recovery from bone biopsy specimens. We systematically studied the effects of a spectrum of decalcification agents on the quantity and quality of RNA and DNA recovered from bone biopsies. Multiple bone biopsies of similar size and cellularity were fixed in 10% neutral-buffered formalin, randomized to various decalcification agents for 2 hours then processed, and embedded. Tissue lysates were obtained from unstained sections and nucleic acid isolated. DNA and RNA were quantified. Assessment of DNA and RNA integrity was accomplished by comparison of the average cycle threshold by polymerase chain reaction of selected housekeeping genes for each agent. Results were then analyzed by 2-sample t test. There was a significant decrease in both DNA and RNA yield and integrity with strong acids (hydrochloric, nitric) vs 14% EDTA and formic acid. DNA yield was (mean nanograms) 6.15 vs 68.68 (P<.001) and RNA was (mean nanograms) 121.53 vs 288.89 (P=.003), respectively. DNA integrity (mean cycle threshold) was 35.79 vs 30.16 (P<.001), and RNA was 33.03 vs 26.5 (P<.001), respectively. Decalcification of bone biopsies with EDTA or formic acid agents was associated with a significant improvement in recovered nucleic acid quantity and quality.

Reactive versus neoplastic bone marrow: problems and pitfalls

Examination of the bone marrow poses several unique challenges to the pathologist: it is a semisolid organ without helpful gross correlation, it exists in a dynamic state with the peripheral blood and other organs of the lymphohemopoietic system, and the diagnosis of diseases affecting bone marrow often depends heavily on ancillary special studies. The bone marrow examination ideally encompasses review of the bone marrow biopsy histology (with or without additional nondecalcified clot preparation material), bone marrow aspirate smear cytology, and the peripheral blood smear; optimal procurement and processing of these samples is critical in ensuring that a maximal level of diagnostic information can be extracted. The pathologist must be aware of the clinical context of the bone marrow and the results of ancillary tests, whether these are ordered by the pathologist or the clinician. A combination of excellent diagnostic samples, appropriate ancillary tests, and knowledge of the clinical context provides the best background to distinguish between the common reactive and neoplastic processes that involve the bone marrow and to avoid diagnostic pitfalls in making these distinctions.

Optimal processing of bone marrow trephine biopsy: the Hammersmith Protocol

Specimens of bone marrow trephine biopsy (BMT) are transported and fixed in acetic acid-zinc-formalin fixative, decalcified in 10% formic acid-5% formaldehyde and processed with other specimens to paraffin-wax embedding. Sections, 1-microm-thick, are cut by experienced histotechnologists and used for haematoxylin and eosin, Giemsa, reticulin silver and other histological stains. Further, all immunohistochemical procedures used in the laboratory, including double immunostaining, can be used on these sections with no or minimal modifications. About 10,000 BMT specimens have been analysed using this procedure since 1997 and diseases involving the bone marrow have been classified successfully. More recently, standardised polymerase chain reaction-based analysis and mRNA in situ hybridisation studies have been conducted. Excellent morphology with good antigen, DNA and RNA preservation is offered by the Hammersmith Protocol.

Ultrasonic Decalcification Offers New Perspectives for Rapid FISH, DNA, and RT-PCR Analysis in Bone Marrow Trephines

The requisite analyses on bone marrow biopsies are increasing: Molecular analyses such as fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR), and reverse transcriptase (RT)-PCR are demanded in addition to morphology and immunohistochemistry to improve diagnostic accuracy. Moreover, analysis of certain molecular prognostic or predictive biomarkers is increasingly mandatory in the assessment of hematologic diseases. In some circumstances, only formalin fixed, bone-containing tissue is available for molecular analysis. Because various fixation and decalcification procedures can impair DNA and RNA quality, there is an urgent need for standardized decalcification protocols which allow FISH and PCR analysis. In this study we developed a routinely applicable decalcification protocol to optimize the molecular analysis method although preserving morphology and immunohistochemical results. Therefore, we compared 2 different approaches including ultrasonic decalcification versus nonultrasonic procedures and ethylenediaminetetraacetate-based reagents versus acid-based ones. In our hands, the combined use of ultrasound and ethylenediaminetetraacetate-based reagents permits successful interphase FISH, PCR, and RT-PCR analysis whereas concomitantly preserving morphology and antigeneicity.

Application of the FICTION technique for the simultaneous detection of immunophenotype and chromosomal abnormalities in routinely fixed, paraffin wax embedded bone marrow trephines

The use of interphase fluorescence in situ hybridisation (FISH) to study cytogenetic abnormalities in routinely fixed paraffin wax embedded tissue has become commonplace over the past decade. However, very few studies have applied FISH to routinely fixed bone marrow trephines (BMTs). This may be because of the acid based decalcification methods that are commonly used during the processing of BMTs, which may adversely affect the suitability of the sample for FISH analysis. For the first time, this report describes the simultaneous application of FISH and immunofluorescent staining (the FICTION technique) to formalin fixed, EDTA decalcified and paraffin wax embedded BMTs. This technique allows the direct correlation of genetic abnormalities to immunophenotype, and therefore will be particularly useful for the identification of genetic abnormalities in specific tumour cells present in BMTs. The application of this to routine clinical practice will assist diagnosis and the detection of minimal residual disease.

HER2 amplification and overexpression is not present in pediatric osteosarcoma: a tissue microarray study

The HER2 gene, located on 17q, encodes a 185-kD transmembrane tyrosine kinase receptor. Amplification of this gene with overexpression of the gene product occurs in about 30% of cases of breast cancer and is considered to be a poor prognostic indicator for this tumor. Results for HER2 expression in osteosarcoma are controversial, with some studies reporting up to 61% of positive cases and others reporting only negative results. Further, expression of HER2 is reported to be a favorable prognostic indicator by some groups and unfavorable by others. The present study used tissue microarrays containing 34 samples of osteosarcoma from 18 patients to analyze HER2 expression by immunohistochemistry and gene copy number by chromogenic in situ hybridization. The microarray included 13 pretreatment biopsies, 11 posttreatment resection specimens, and 10 resected metastases and comprised 18 osteoblastic, 6 chondroblastic, 5 fibroblastic, and 5 mixed subtypes. HER2 protein expression was seen in 4 of 34 (12%) tumor samples that originated from 2 of 18 patients (11%). The staining pattern was consistently weak and focal, and immunohistochemical overexpression of the HER2 protein, defined as complete membrane positivity, was never observed. Further, the presence of HER2 gene amplification was not detected in any osteosarcoma by chromogenic in situ hybridization. Therefore, therapies based on antibodies directed against the HER2 protein are unlikely to have much value in the treatment of pediatric osteosarcomas. From a technical standpoint, this study also demonstrates the value of tissue microarrays in screening tumors at the protein and gene levels using conventional light microscopy.

Effect of monoenergetic neutron irradiation on the postnatal development of the cochlea in C3H/HeN mice

To investigate the toxic effect of neutrons at energies of approximately 1MeV on the ear, we exposed 7-day-old mice to 1.0 Gy of monoenergetic neutrons (1.026 MeV) or (137)Cs gamma rays, and assessed subsequent morphological changes in the inner ear by light and scanning electron microscopy. Monoenergetic neutrons, but not gamma rays, caused acute changes in the ear. The epithelium of the greater epithelial ridge in the organ of Corti had disappeared by 72 hr post-irradiation, as a result of epithelial apoptosis observed 6 hr post-irradiation. Radiation could induce apoptotic cell death of the epithelium of the greater epithelial ridge at 3 or 4 days of age. Protruding structures were detected on the surface of the hair cells by 72 hr post-irradiation. The neutron-irradiation also caused the apoptotic cell death of epithelial cells at the nasal conchae, and subsequent acute otitis media continued until 10 weeks of age.

Bone marrow histopathology in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCL) account for 10-15% of all lymphoproliferative disorders in the western hemisphere. In PTCL, bone marrow biopsy is performed to establish the diagnosis, rule out other pathology, assess the extent of disease and monitor treatment response. The frequency and histology of bone marrow involvement varies greatly between different clinicopathological entities recognized by the World Health Organisation (WHO) classification, reflecting the differences in the underlying biology. Some lymphomas, such as angioimmunoblastic T-cell lymphoma, show nodular and/or interstitial pattern of infiltration with accompanying reactive changes. Others, including hepatosplenic T-cell lymphoma and large granular lymphocyte leukaemia, are characterized by intrasinusoidal infiltration. In many instances the pathological features are subtle and immunohistochemical and molecular studies are required for the diagnosis. Histological appearances may overlap with a variety of reactive T-cell proliferations and other malignancies. Furthermore PTCL frequently induce secondary changes in the marrow that may obscure the neoplastic infiltrate. The diagnosis often requires critical integration of the information obtained from clinical features, peripheral blood, bone marrow aspirate and biopsy findings. In this article we review the histopathology of bone marrow biopsy in PTCL within the context of the new WHO classification.

Distinct chromosomal aberrations in sinonasal mucosal melanoma as detected by comparative genomic hybridization

Sinonasal mucosal melanomas are the most frequent mucosal melanomas and arise from melanocytes located in the nasal cavity and the paranasal sinuses. The melanoma types, cutaneous melanoma, uveal melanoma, and mucosal melanoma, differ in etiology, geographic distribution, and clinical behavior. Genetic alterations have been previously studied in cutaneous and uveal melanomas but, to the best of our knowledge, not in mucosal melanomas. Comparative genomic hybridization (CGH) was performed on 14 routinely processed sinonasal mucosal melanomas. Furthermore, ploidy analysis was performed on 11 tumors to provide complementary data on the DNA index. The CGH profiles of sinonasal mucosal melanomas show remarkably consistent alterations: chromosome arm 1q is gained in all tumors and gains of 6p and 8q are present in 93 and 57%, respectively. Comparison of CGH data with both the common variants of cutaneous melanoma and uveal melanoma revealed that sinonasal mucosal melanomas harbor a distinct pattern of chromosomal abnormalities. Ploidy analysis also showed that diploid tumors exhibit gains of 1q and alterations of chromosome 6 (3 of 3 cases tested), whereas clear-copy gains and high-copy gains were seen only in triploid and tetraploid tumors (6 of 8 cases tested). This indicates that alteration of chromosomes 1 and 6 may precede polyploidization and formation of clear-copy gains and high-copy gains.

Amplification of the androgen receptor gene in bone metastases from hormone-refractory prostate cancer

The aim of this study was to examine the prevalence of androgen receptor (AR) amplification in metastases to bone and other sites in patients with hormone-refractory prostate cancer (HRPC) and to compare these findings with those in pretreatment primary tumour samples from the same patients. Tissue from 24 patients with HRPC was available for study, together with 13 primary tumour specimens. AR gene amplification and copy number for X-chromosome were assessed by fluorescence in situ hybridization (FISH) using a SpectrumOrange-labelled probe at locus Xq11-13 for the AR gene and a SpectrumGreen-labelled alpha-satellite probe for the X-chromosome (Vysis, UK, Ltd.). A minimum of 20 nuclei were scored in each of three tumour areas by two independent observers. Samples from 18/24 patients with HRPC (12 bone marrow biopsies, three local tumour recurrences, and three lymph nodes) and nine primary tumour specimens were adequate for FISH analysis. Results were expressed as a mean ratio of AR gene copy number : mean X-chromosome number, with a ratio of greater than 1.5 defined as amplification. AR gene amplification was seen in 9/18 (50%) cases of HRPC and in none of the primary (untreated) tumour specimens (p = 0.0048, Fisher's exact test). For the 12 bone marrow samples, AR gene amplification occurred in 5/12 (38%) cases. Elevated copy number for chromosome X occurred in 3/18 (17%) HRPC and 4/9 (44%) matched primary tumours. This study shows for the first time that AR gene amplification can be demonstrated by FISH in bone metastases from HRPC patients. Because bone marrow biopsies can be obtained from most patients with HRPC, the findings provide a rational basis for the routine selection of patients who may respond more favourably to second-line anti-androgen therapy.