Chromogenic in-situ hybridization: a viable alternative to fluorescence in-situ hybridization in the HER2 testing algorithm.

Assessment of human epidermal growth factor receptor-2 status is standard practice in women with breast cancer. Most laboratories use immunohistochemistry as a screening test, with equivocal results confirmed by fluorescence in-situ hybridization (FISH). Chromogenic in-situ hybridization (CISH) is a relatively new method for detection of gene amplification using a peroxidase reaction, which can be viewed using a standard light microscope. This study was undertaken to validate CISH as a method for assessing human epidermal growth factor receptor-2 gene amplification. The gene amplification status of human epidermal growth factor receptor-2 immunohistochemistry negative (0/1+, n = 69; Group 1), immunohistochemistry positive (3+, n = 50; Group 2) and equivocal tumor samples (2+, n = 135; Group 3) was evaluated by FISH and CISH, and the concordance between FISH and CISH results calculated. In Group 1, 67/69 cases did not show amplification by CISH and 69/69 showed no amplification by FISH. Two cases were discordant; therefore, fluorescence/CISH concordance was 97%. In Group 2, 46/50 cases were amplified by FISH and 47/50 cases were amplified by CISH; three cases were not amplified by either method (immunohistochemistry false-positives). Only one case showed discordant FISH and CISH results, making the fluorescence/CISH concordance 98%. In Group 3, 89/135 cases were not amplified and 37/135 were amplified by both methods. Nine cases were discordant, giving a fluorescence/CISH concordance of 93%. The discordant cases were those with very low or borderline amplification with FISH. The high level of concordance between FISH and CISH seen in this study suggests that CISH may be a viable alternative to FISH for use in the human epidermal growth factor receptor-2 testing algorithm.     

双色银染原位杂交与荧光原位杂交检测胃癌患者HER2基因状态

Objective To investigate the advantages and disadvantages of dual-color silverenhanced in-situ hybridization(DSISH)and fluorescence in-situ hybridization(FISH)for determination of HER2 gene status in gastric carcinoma and to evaluate tlle feasibility of DSISH.Methods Eighty cases of primary gastric or gastroesophageal junction adenecarcinomag diagnosed and treated surgically from January to March.2009 at the West China Hospital were enrolled in the study.Automated immunohistochemistry (IHC)staining,FISH and automated DSISH were carried out to detect the HER2 status,respectively,and the concordance ofthe three techniques was then evaluated.Results DSISH and FISH failed initially,but repeated detection Was successful in 5 eases.Gene amplification was detected in 12/13 IHC 3+ cases in DSISH and in 11/13 IHC 3+ cases in FISH.In 6 IHC 2+cages, the amplification rate was both 1/6;in 18 IHC 1+cases.the amplifieation rate was both 2/18.No amplification Was observed in 43 IHC 0 cases.Only one of the 80 cases showed discrepancy.and tIlerefore the overall concordance between FISH and DSISH Wag 98.8%(κ=0.958,P＜0.01).Conclusions DSISH represents a novel approach for the determination of HER2 status in gastric carcinoma, and the overall concordance between DSISH and FISH is excellent.Despite their advantages and disadvantages.DSISH is more feasible and practical for routine application in surgical pathology.     

双色银染原位杂交与荧光原位杂交检测胃癌患者HER2基因状态

目的 比较双色银染原位杂交(DSISH)与荧光原位杂交(FISH)两种技术在胃癌HER2检测中的优缺点,评价DSISH用于胃癌患者HER2基因扩增状态检测的可行性.方法 收集2009年1月至3月在四川大学华西医院行根治性手术的原发性胃或胃食管交界处腺癌80例,行全自动免疫组织化学(IHC)染色检测HER2蛋白表达,所有标本行FISH和全自动DSISH检测HER2基因状态,比较不同检测方法之间的符合率.结果 DSISH和FISH初检均有5例失败,经重复检测后结果满意.IHC检测3+的13例中DSISH检测12例、FISH检测11例为HEB2基因扩增;IHC检测2+的6例中DSISH、FISH检测均有1例为基因扩增;IHC检测1+的18例中DSISH、FISH检测均有2例为基因扩增;IHC检测为0的43例中DSISH、FISH检测均无基因扩增.80例原位杂交病例中,仅1例检测结果不一致(DSISH有基因扩增而FISH无基因扩增),两种方法的总体符合率为98.8%(79/80,κ=0.958,P＜0.01).结论 DSISH技术用于胃癌HER2基因检测结果与FISH符合率高.DSISH与FISH检测各有优缺点,DSISH更具有可行性和实际应用价值.

Abstract：

Objective To investigate the advantages and disadvantages of dual-color silverenhanced in-situ hybridization(DSISH)and fluorescence in-situ hybridization(FISH)for determination of HER2 gene status in gastric carcinoma and to evaluate tlle feasibility of DSISH.Methods Eighty cases of primary gastric or gastroesophageal junction adenecarcinomag diagnosed and treated surgically from January to March.2009 at the West China Hospital were enrolled in the study.Automated immunohistochemistry (IHC)staining,FISH and automated DSISH were carried out to detect the HER2 status,respectively,and the concordance ofthe three techniques was then evaluated.Results DSISH and FISH failed initially,but repeated detection Was successful in 5 eases.Gene amplification was detected in 12/13 IHC 3+ cases in DSISH and in 11/13 IHC 3+ cases in FISH.In 6 IHC 2+cages, the amplification rate was both 1/6;in 18 IHC 1+cases.the amplifieation rate was both 2/18.No amplification Was observed in 43 IHC 0 cases.Only one of the 80 cases showed discrepancy.and tIlerefore the overall concordance between FISH and DSISH Wag 98.8%(κ=0.958,P＜0.01).Conclusions DSISH represents a novel approach for the determination of HER2 status in gastric carcinoma, and the overall concordance between DSISH and FISH is excellent.Despite their advantages and disadvantages.DSISH is more feasible and practical for routine application in surgical pathology.     

Dual-colour chromogenic in-situ hybridization is a potential alternative to fluorescence in-situ hybridization in HER2 testing

Hwang C‐C, Pintye M, Chang L‐C, Chen H‐Y, Yeh K‐Y, Chein H‐P, Lee N & Chen J‐R
(2011) Histopathology 59 , 984–992 Dual‐colour chromogenic in‐situ hybridization is a potential alternative to fluorescence in‐situ hybridization in HER2 testing Aim: Dual‐colour chromogenic in‐situ hybridization (dc‐CISH) is an emerging methodology for characterizing genomic alterations. This study was aimed at evaluating the performance of a dc‐CISH kit (ZytoVision) in determining human epidermal growth factor receptor 2 (HER2) status in breast cancer. Methods and results: Two hundred and twenty‐eight invasive breast carcinomas arranged in tissue microarrays were analysed in parallel with dc‐CISH, fluorescence in‐situ hybridization (FISH), and immunohistochemistry. Of 227 tumours with available FISH and dc‐CISH results, HER2 amplification and non‐amplification were detected in 49 (21.6%) and 178 (78.4%) tumours, respectively, by both assays. The concordance between dc‐CISH and FISH results showed 100% agreement (κ‐coefficient = 1.00). Immunohistochemically, 162 (71%), 25 (11.0%) and 41 (18%) tumours were scored 0/1+, 2+, and 3+, respectively. The corresponding results with both FISH and dc‐CISH demonstrated HER2 amplification in two (3.2%), nine (36%) and 38 (93%) tumours, respectively. Complete consensus among these three methods was observed in 197 cases, representing 98% of all 3+ and 0/1+ tumours (κ‐coefficient = 0.92). Confirmatory testing of 25 2+ tumours showed complete consensus between FISH and dc‐CISH. Conclusions: dc‐CISH is a promising alternative to FISH in HER2 testing, and the single‐institute incidence of HER2 amplification in breast cancer in Taiwan is 21.2%.     

FISH应用于植入前遗传学诊断对高风险胚胎检测的研究

目的对固定好的单卵裂球进行FISH检测,在最短的时间内获得清晰可靠的信号,进行临床分析.方法选取发育不良的高风险胚胎分别进行分开变性和共变性后杂交的单细胞FISH,统计并分析其信号结果.结果共变性法信号获得率较分开变性法为高,并且信号获得率与变性方法相关(P=0.0486);共有9枚胚胎,42个卵裂球固定良好,其中二倍体信号36个,单倍体信号2个,21号染色体异常的胚胎为4︰9.结论初探分析人IVF废弃胚胎21号染色体异常几率较高.     

Fluorescence in-situ hybridization analysis for melanoma diagnosis

Melanocytic proliferation constitutes a heterogeneous group of lesions with remarkable differences in their biology and clinical outcome. Thus, accurate histological diagnosis of these cases is mandatory to establish the most appropriate surgical treatment and follow-up. Although histological examination alone is usually sufficient to identify melanomas among the greater number of nevi, the definition of the benign or malignant nature of a subset of melanocytic tumours, exhibiting atypical features, is a challenging task. Novel techniques that may assist in the histopathological diagnosis in difficult cases have been extensively researched over recent years. Fluorescence in-situ hybridization (FISH), performed with a panel of four probes, including three locus-specific identifier (RREB1, MYB, and CCND1) genes, seems to represent a sensitive and specific molecular tool for the diagnosis of non-ambiguous melanocytic lesions. Some studies have agreed that FISH may be an ancillary diagnostic instrument, but cannot replace light microscopy, to distinguish benign nevi from malignant melanomas in daily practice. However, in the context of ambiguous melanocytic tumours, results are still controversial, and additional and substantial work is needed to develop reliable probes that may identify, with high sensitivity, specific subsets of ambiguous melanocytic lesions, including spitzoid proliferation.     

Comparison between blood culture and in-situ hybridization of bacteria

We compared blood culture and in situ hybridization method (Hybrisep) to detect bacteria in blood samples. One thousand and two hundred and sixty nine blood culture samples were tested in 2003 in our hospital. One hundred and sixty seven samples (13.1%) were positive for bacteria. Total number of detected bacteria was 178. Of 178 bacteria, 49.4% was gram positive, 32.6% was gram negative, 13.5% was Candida spp., and 4.5% was anaerobic. Twenty five samples were tested with both blood culture and Hybrisep. Three samples were positive for both methods, and 13 samples were negative for both methods. The identical results were obtained in 64% of samples. Although the microscopic determination of positive signals in Hybrisep requires trained skills, Hybrisep may be a rapid and sensitive method providing valuable information to diagnose sepsis with an automated equipment and an increased number of probes.     

Sex chromosome differentiation revealed by genomic in-situ hybridization

In this work, genomic in-situ hybridization (GISH) was used to study the sex chromosome molecular differentiation on chromosomes of male and female individuals of the isopod crustacean Asellus aquaticus. As a composite hybridization probe, we contemporaneously used male and female whole genomic DNA differently labelled in the presence of an excess of unlabelled DNA of the female homogametic sex. The karyotype of A. aquaticus normally displays eight homomorphic chromosome pairs, but a heteromorphic sex chromosome pair is present in about a quarter of the males of a natural population previously identified by us. GISH did not reveal any sex chromosome molecular differentiation on the male and female homomorphic sex chromosome pair, and the karyotypes of these individuals were equally labelled by the male- and female-derived probe, while the heteromorphic Y chromosome showed a differentially labelled region only with the male-derived probe. This region evidently contains male-specific sequences but, because no similar hybridized region is observed on the male homomorphic chromosome pair, they are probably not important for sex determination but represent a molecular differentiation acquired from the Y chromosome. This revised version was published online in July 2006 with corrections to the Cover Date.     

In-vitro decondensation of human spermatozoa for fluorescence in-situ hybridization

In order to enhance the efficiency of fluorescence in-situ hybridization(FISH) on human interphase spermatozoa, a simple method forpartial decondensation of human spermatozoa chromatin is described.The spermatozoa were washed once in 0.01 M Tris and decondensedusing 10 mM dithiothreitol in 0.05 M Tris for 10–50 min,before being spread onto clean slides. Sperm samples were observedevery 10 min under a phase-contrast microscope in order to modifythe duration of the decondensation process. Using several centromericor YAC probes in multicolour FISH, high hybridization rateswere obtained. FISH/human spermatozoa/in-vitro decondensation     

Clinical experience of sex determination by fluorescent in-situ hybridization for preimplantation genetic diagnosis.

In our centre we started using fluorescent in-situ hybridization (FISH) technique for sexing in couples with sex-linked diseases in May 1995. Probes specific for chromosomes X, Y and 18 were applied, allowing us to detect simultaneously both gender and ploidy status. The efficiency of the FISH procedure is 90.4% per biopsied blastomere or 95.2% per biopsied blastomere with a distinct nucleus visible at spreading. Up to December 1997, we treated 15 couples (20 treatment cycles) at risk for X-linked recessive disease and two couples with Yq deletion (two treatment cycles) with the aim of transferring only female embryos. In one cycle, no embryos suitable for biopsy were obtained and in five cycles no normal female embryos were available at diagnosis. In the remaining 16 cycles, transfer was possible and six pregnancies ensued: one miscarriage has occurred and six children have been born from the other five pregnancies. The implantation rate (fetal sacs) per transferred embryo was 20.8%. In 98 (61%) of the 161 diagnosed embryos, a diploid status was observed in one or in both biopsied blastomeres. In 10 out of the 161 (6.2%) embryos a heterogeneity among the two biopsied blastomeres was found: a diploid nucleus in one blastomere and a non-diploid pattern or binuclear status in the other. In the remaining 53 (32.9%) out of 161 diagnosed embryos, the biopsied blastomeres were abnormal. The embryos that were not transferred or frozen were further analysed. When two sex chromosomes and two autosomes were present in the biopsied blastomere, the sex determination of the biopsied blastomere was never in conflict with the sex determination in the rest of the embryo. Furthermore, if the biopsied cell was diagnosed as abnormal (triploid, aneuploid, chaotic) the embryo was indeed completely abnormal or at least mosaic. A FISH error could not be excluded in two embryos (1.2%); however, a wrong gender determination did not result from this.     

Distribution of ehrlichiae in tissues as determined by in-situ hybridization

Specific identification of ehrlichiae in the tissues and determination of their distribution is difficult. In this study, an in-situ hybridization method was developed to detect ehrlichial 16S rRNA in tissue specimens from mice experimentally infected with the HF strain. This strain is closely related to Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis. HF strain-specific 16S rRNA was detected in endothelial cells and monocyte-macrophages in the liver, lungs, bone marrow, spleen, lymph nodes, and large and small intestinal tissues. The results suggest that the in-situ hybridization method with a digoxigenin-labelled RNA probe specific to ehrlichial 16S rRNA will be useful for post-mortem diagnosis and for the histopathological investigation of ehrlichial infection.     

Towards unlimited colors for fluorescence in-situ hybridization (FISH)

We describe a FISH protocol that allows rehybridization of complex DNA probes up to four times to the same specimen. This strategy, which we termed ReFISH, opens a wide range of new applications to conventional band pass filter epifluorescence microscopy. These include M-FISH karyotyping and cross-species color banding that emulate multiplex probe sets labeled with up to 12 fluorochromes in sequential hybridizations to the same specimen. We designed a human 24-color karyotyping probe set in combination with a 29-color cross-species color banding probe set using gibbon painting probes. Applying the ReFISH principle, 53 painting probes on individual metaphases were discriminated. This allowed simultaneous screening for inter- and intrachromosomal rearrangements on normal human diploid cells, a HeLa derived cell line, and highly rearranged gibbon chromosomes. Furthermore, the present ReFISH experiments successfully combine 24-color FISH with laser scanning confocal microscopy to study the 3D organization of all 46 human chromosome territories in individual interphase cell nuclei.     

Analysis of human sperm-derived pronuclei by three-colour fluorescent in-situ hybridization

We describe a modification of the human sperm-zona-free hamster egg fusion method that permits the study of aneuploidy in sperm-derived pronuclei by multicolour fluorescent in-situ hybridization (FISH). Zona- free hamster eggs and human spermatozoa were fused and cultured for 15 h in the presence of colcemid (1 microg/ml of medium) to obtain hamster oocytes arrested at metaphase II and human spermatozoa at the pronuclear stage. By applying a whole human genomic DNA probe we confirmed that 100% of pronuclei tested (372/372) were of human origin. One-colour fluorescent in-situ hybridization using a centromeric 18 probe was applied to 919 pronuclei with different dithiothreitol (DTT) pretreatments: 50 mM (10 min) or 25 mM (20 and 25 min). The highest hybridization efficiency was obtained with treatment with 25 mM DTT for 20 min (90.3%). Sex chromosome aneuploidy was analysed by three-colour FISH in a total of 2596 pronuclei from a normal donor. Hybridization efficiency was 98.6%. The disomy rates for X, Y and XY chromosomes (0.11, 0.04 and 0.08% respectively) were similar to data reported for sperm nuclei by three-colour FISH and to those obtained in sperm chromosomes. These results suggest that selection of potentially fertile spermatozoa (spermatozoa able to fertilize zona-free hamster eggs and produce a pronucleus) does not imply chromosomal selection.      

Biopsied testis cells of four 47,XXY patients: fluorescence in-situ hybridization and ICSI results.

BACKGROUND: A testis biopsy was performed for four non-mosaic 47,XXY azoospermic patients. Spermatozoa were found in three cases and frozen before ICSI. We analysed the various cells found in the four samples by multicolour fluorescence in-situ hybridization (FISH), to evaluate the meiosis and spermatogenesis possibilities of the 47,XXY and 46,XY testis cell lines, and to estimate aneuploidy rate in the resulting spermatids and spermatozoa. METHODS AND RESULTS: Testis diploid cells (either somatic or premeiotic), meiotic, and post-meiotic haploid germ cells were hybridized with probes for chromosomes X, Y and 18. The only patient with no spermatozoa had a homogeneous diploid XXY constitution in the testis; the three other patients presented two cell populations (46,XY and 47,XXY) among their diploid testis cells. All the observed pachytene figures were XY; no XXY pachytene figure was found. The aneuploidy rate among post-meiotic cells for chromosomes X,Y and 18 was 6.75% (5/74). This rate was 1.5% (2/133) for control. Three couples underwent ICSI; four attempts were made, one healthy baby was born. CONCLUSION: FISH results suggest that only 46,XY cells can undergo meiosis.     

Pregnancies following pre-conception diagnosis of common aneuploidies by fluorescent in-situ hybridization

Chromosomal aneuploidies contribute considerably to the lowpregnancy rate in in-vitro fertilization (IVF). The objectiveof this experimental work was to explore the possibility ofdetecting common aneuploidies in oocytes by polar body sampling.The study included 45 infertile patients of advanced maternalage participating in an IVF programme. The first polar bodywas removed prior to fertilization or both the first and secondpolar bodies were removed after fertilization and studied byfluorescent in-situ hybridization (FISH) using chromosome-specificprobes for chromosomes X, 18 and/or 13/21. Of 155 oocytes withFISH results, 36 demonstrated chromosomal abnormalities. Of119 oocytes predicted to be free from aneuploidy of chromosomesX, 18 and/or 13/21, 72 were normally fertilized, cleaved andtransferred in 23 treatment cycles, which resulted in two healthydeliveries and three ongoing pregnancies confirmed to be unaffectedby chorionic villous sampling. The method may appear usefulfor the detection of oocytes with common chromosomal aneuploidiesin IVF patients of advanced maternal age. chromosomal aneuploidies/fluorescent in-situ hybridization/human first and second polar bodies/pre-conception/preimplantation genetic diagnosis     

Gene identification by chromosomal in-situ hybridization, microdissection and polymerase chain reaction amplification

This paper describes a theoretical method by which candidate genes for inherited diseases can be identified by polymerase chain reaction amplification and subsequent cloning of organ-specific complementary deoxyribonucleic acid libraries hybridized in situ to, and subsequently dissected from, the cognate chromosome. A specific application of this technique to isolate genes related to genetic haemochromatosis is outlined.