Bright-field HER2 dual in situ hybridization (DISH) assay on breast cancer cell blocks: a comparative study with histological sections

Background

HER2 testing for samples from recurrent or metastatic disease is recommended by the 2013 update of the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines and cytological analysis can be applied to several types of metastatic lesions. However, the practical method to assess the HER2 testing of breast cancer cytology specimens has yet to be resolved. Therefore, we conducted the bright-field HER2 dual in situ hybridization (DISH) assay on cell blocks (CBs) prepared from breast cancer cell samples as a validation study before clinical use.

Methods

CBs were prepared from tumor cell samples collected from 54 surgically excised breast tumors. The cells were fixed in 10 % buffered formalin for 16–28 h, and embedded in paraffin. The INFORM HER2/neu Dual ISH DNA Probe Cocktail was used for the DISH assay on the Ventana BenchMark ULTRA (Roche Diagnostics).

Results

Successful results were obtained in 51 of 54 CB specimens, and the results from the CB specimens were in agreement with those from the histological sections in 48 of the 51 cases (concordance rate, 94 %; kappa, 0.846). The intraclass correlation coefficient (ICC) between the CB and histological specimens in the continuous HER2/CEP17 signal count ratio was 0.89 (95 % CI 0.81–0.93), and the Pearson’s CC was 0.91 (95 % CI 0.85–0.94).

Conclusion

The HER2 DISH assay, utilizing 10 % buffered formalin-fixed CB, would be a reliable and ideal method to assess the HER2 gene status of breast cancer cytological specimens.

     

The expression of C-myc and N-ras oncogenes in human hepatocellular carcinoma—Anin situ hybridization study on paraffin embedded tissue sections

In this research, we investigated the expression of C-myc and N-ras mRNAs on 21 cases paraffin-embedded tissue sections of hepatocellular carcinoma (HCC) usingin situ hybridization technique with biotinylated labelled cDNA probes. Of 21 cases of hepatoma, C-myc mRNA was positive-expressed in 9 cases (42.9%) and N-ras positive in 4 cases (19%) in hepatoma cells, and C-myc and N-ras positive in 4 and 1 cases respectively in peritumor hepatocytes. C-myc mRNAs were localized within cytoplasms of both hepatoma cells and peritumor hepatocytes. However, the positive intensities of C-myc and N-ras mRNAs in hepatoma cells were much greater than those in peritumor hepatocytes. The results indicated that C-myc and N-ras oncogenes were overexpressed in HCC, and may play an important role in coordinatively maintaince of the malignant phenotypes in HCC. Supported by the National Nature Science Foundation of China (No. 3880376) and Medical Science Research Foundation of PLA.     

BCL2 expression correlates with metastatic potential in pancreatic cancer cell lines

BACKGROUND: Programmed cell death (termed apoptosis) regulates normal tissue homeostasis. Loss of local paracrine signals and intercellular adhesion molecules are potent inducers of apoptosis and thereby eliminate normal cells that may have escaped beyond the confines of the local organ environment. Dysregulation in the expression of the BCL2 gene family, the prototypic regulators of apoptosis, is a common occurrence in cancer and imparts resistance to standard triggers of apoptosis. Therefore, the authors sought to examine whether abnormal BCL2 gene family expression correlated with resistance to apoptosis and increased metastatic potential in pancreatic carcinoma. METHODS: The authors examined BCL2 expression and apoptotic sensitivity in three panels of human pancreatic cancer cell lines that possess varying metastatic potential. Stable transfectants were generated that overexpress BCL2. These transfectants were then analyzed for differences in metastasis formation in athymic mice. RESULTS: Among the isogenic panels of pancreatic cancer cell lines, BCL2 expression levels correlated with metastatic potential. Highly metastatic variants of each family of cell lines were more resistant to induction of apoptosis. Finally, using the BCL2 transfectant in a xenograft model, elevated BCL2 expression led to a higher incidence of metastases. CONCLUSIONS: The authors conclude that increased BCL2 expression correlates with apoptotic resistance and metastatic potential; dysregulation of BCL2 expression may be involved in the metastatic progression of pancreatic carcinoma.     

Immunohistochemical demonstration of estrogen receptors on routine paraffin sections of breast carcinomas: a comparison with frozen sections and an enzyme immunoassay.

In this study the monoclonal antibody ER-ICA (HSpy222) to human estrogen receptor (ER) protein and the peroxidase-antiperoxidase method was used to detect the presence of ER in 83 cryostat sections and in 68 paraffin sections pretreated with pronase in a total of 86 primary breast cancers. In 72 out of the 86 studied cases, a comparative evaluation was performed between the semiquantitative ER-ICA method and the quantitative enzyme immunoassay ER-EIA. A good correlation was found between the semiquantitative ER-ICA results in cryostat and paraffin sections (95.38%; p less than 0.01) in a total of 65 compared cases, concerning both the percentage of ER-positive or negative cells and the staining intensity. In addition, the overall appraisal of the lesion as ER-ICA-positive or ER-ICA-negative as well as the ER-ICA staining intensity and the proportion of ER-ICA stained cancer cells, in both cryostat and paraffin sections, correlated significantly with the mean values of fmol ER/mg determined by the enzyme immunoassay ER-EIA. The performance of the ER-ICA method on paraffin sections as used in the present study proved to be a reliable and reproducible immunohistochemical technique.     

Human papillomavirus genome detection by in situ hybridization in fine-needle aspirates of metastatic lesions from head and neck squamous cell carcinomas

BACKGROUND: Patients with head and neck squamous cell carcinoma (HNSCC) often present with metastatic disease. The diagnosis of metastatic lesions usually is determined by fine-needle aspiration. Human papillomavirus (HPV) is now being considered as a causative agent in a subset of HNSCC. The objectives of this study were, first; to search for the presence of HPV DNA by in situ hybridization (ISH) in metastatic lesions from HNSCC using alcohol-fixed, archival, cytopathologic material; second, to characterize the cytologic features of HPV-positive metastatic lesions of HNSCC; and, third, to determine whether there is a correlation between the presence of HPV DNA and the origin of metastatic lesions. METHODS: The authors performed chromogenic ISH analysis for HPV DNA on fine-needle aspiration materials from metastatic lesions from 26 patients with HNSCC. Along with the ISH analysis, a detailed cytologic review was performed, and cytopathologic features were recorded. The HPV DNA status in metastatic lesion was correlated with cytopathologic features and primary tumor location. RESULTS: The integration of HPV DNA was visualized microscopically on tumor cell nuclei in 15% of aspirates. The anatomic locations of the study samples were as follows: 16 lymph node aspirates (11 cervical lymph nodes and 5 lymph nodes at other sites other), 5 tracheostomy sites, and 5 miscellaneous sites located on the head and neck area. Cytologic review revealed 13 keratinized and 13 nonkeratinized metastatic tumors. HPV DNA was detected in four metastatic sites (three lymph nodes and one tracheostomy site). All HPV DNA-positive tumors were of the nonkeratinizing type (P < 0.05; Fisher exact test). The origins of HPV-positive tumors included two laryngeal sites, one nasopharyngeal site, and one oral cavity site. CONCLUSIONS: The current findings showed that archival cytology slides can be used for HPV DNA detection with ISH. The results also showed that HPV DNA-containing HNSCC has distinctively nonkeratinizing cytologic features. The authors concluded that HPV DNA not only is involved in the initiation of tumoral processes but also plays an important role in the development of metastatic disease.     

Detection of copy number alterations in metastatic melanoma by a DNA fluorescence in situ hybridization probe panel and array comparative genomic hybridization: a southwest oncology group study (S9431).

PURPOSE: Gene copy number alteration (CNA) is common in malignant melanoma and is associated with tumor development and progression. The concordance between molecular cytogenetic techniques used to determine CNA has not been evaluated on a large set of loci in malignant melanoma. EXPERIMENTAL DESIGN: A panel of 16 locus-specific fluorescence in situ hybridization (FISH) probes located on eight chromosomes was used to identify CNA in touch preparations of frozen tissue samples from 19 patients with metastatic melanoma (SWOG-9431). A subset (n = 11) was analyzed using bacterial artificial chromosome (BAC) array comparative genomic hybridization (aCGH) of DNA isolated directly from touch-preparation slides. RESULTS: By FISH, most samples showed loss near or at WISP3/6p21, CCND3/6q22, and CDKN2A/9p21 (>75% of samples tested). More than one third of CDKN2A/9p21 losses were biallelic. Gains of NEDD9/6p24, MET/7q31, and MYC/8q24 were common (57%, 47%, and 41%, respectively) and CNA events involving 9p21/7p12.3 and MET were frequently coincident, suggesting gain of the whole chromosome 7. Changes were confirmed by aCGH, which also uncovered many discreet regions of change, larger than a single BAC. Overlapping segments observed in >45% of samples included many of the loci analyzed in the FISH study, in addition to other WNT pathway members, and genes associated with TP53 pathways and DNA damage response, repair, and stability. CONCLUSIONS: This study outlines a set of CNAs at the gene and regional level, using FISH and aCGH, which may provide a benchmark for future studies and may be important in selection of individual therapy for patients with metastatic malignant melanoma.     

Reduced apoptotic levels in squamous but not basal cell carcinomas correlates with detection of cutaneous human papillomavirus

We have investigated the apoptotic levels and expression of the apoptotic inducer Bak in non-melanoma skin cancers. Squamous cell carcinomas of known human papillomavirus status from immunocompetent patients were analysed for the expression of the Bak protein, and the expression profile was compared both to the presence of apoptotic cells and the proliferation marker Ki-67. We demonstrate an inverse correlation between human papillomavirus positivity and Bak expression in squamous cell carcinomas, with concomitantly fewer apoptoic cells being detected in the human papillomavirus positive tumours. Bak expression was not observed in basal cell carcinomas irrespective of human papillomavirus status, suggesting that Bak only plays a role in signalling apoptosis in squamous, but not basal, cell cancers. No differences were observed in the proliferation rates between papillomavirus positive and negative squamous cell tumours. However, a significant decrease in the number of apoptotic cells was observed in human papillomavirus-positive squamous cell carcinomas which suggests that the virus may have significantly altered the relationship between proliferation and apoptosis in a proportion of these tumours.     

Secondary chromosome changes in mantle cell lymphoma: cytogenetic and fluorescence in situ hybridization studies.

To better define the incidence and nature of secondary chromosome anomalies in mantle cell lymphoma (MCL) carrying the t(11:14)/BCL1 rearrangement, cytogenetic and fluorescence in situ hybridization studies (FISH) were performed in 42 patients (39 classical histology, 3 blastoid variant), using 6q21, 9p21/p16, 13q14, 17p13/p53 and chromosome-12-specific probes. Karyotypes from 89 cases published in 5 recent series including patients diagnosed in a homogeneous fashion were reviewed. In our series, FISH confirmed the interpretation of the karyotype in all cases and disclosed cryptic chromosome deletions in a sizeable fraction of cases. One patient (2.4% of total) was found with a cryptic 9p21 deletion by FISH. Two cases (4.8%) had a 6q21 deletion at CCA and at FISH; +12 was found in three cases by CCA plus nine by FISH (28.6%); 13q14 deletion was found in six cases by CCA plus 16 by FISH (52.4%), 17p13 deletion in three cases by CCA plus 8 by FISH (26.2%). In 131 patients (42 present series plus 89 in the literature) secondary chromosome aberrations seen by conventional cytogenetic analysis in more than 5 cases included deletions/translocations (del/t) 6q15-23 [15 cases]; -13 [14 cases]; del/t 1p21-31 [12 cases]; +3q [11 cases]; del/t 17p [9 cases]; 8p translocations and del(Y) [8 cases each]; -20 [7 cases]; 13q14 deletion, del/t 11q22-23, del/t 9q, del(10)(q22q24), -20, -21, -22 and -X [6 cases each]. We arrived at the following conclusions: i) though no secondary anomaly is specific for MCL, there is a distinct profile of recurrent chromosome lesions in MCL with 1p21-31 deletions, 8p translocations, 11q22-23 anomalies having a strong association with CD5+ B-cell lymphomas of low-to-intermediate grade histology; ii) FISH enabled the detection of cryptic chromosome 12, 13q and 17p rearrangements in a sizeable fraction of cases; iii) 9p21/p16 deletions did not occur at a high incidence in this series, possibly because of the low number of cases with blastoid variant.     

Detection of translocations affecting the BCL6 locus in B cell non-Hodgkin's lymphoma by interphase fluorescence in situ hybridization.

Structural alterations in 3q27 affecting the BCL6 locus are among the most frequent changes in B-NHL. The aim of the present study was to establish an interphase-FISH assay for the detection of all diverse BCL6 translocations in B-NHL. Two different approaches were tested, one using a PAC-clone spanning the major breakpoint region (MBR) of BCL6 (span-assay), and another using two BAC clones flanking the MBR (flank-assay). Interphase FISH with the span-assay detected the various BCL6 translocations in seven B-NHL cell lines. The dual-color flank-assay was evaluated in two laboratories independently: in normal controls, the cutoff level for false-positive signals was 2.6%, whereas the cutoff level for false-negatives in the seven cell lines was 7.5%. To test the feasibility of the FISH strategies, 30 samples from patients with B-NHL with cytogenetic abnormalities of 3q27 were evaluated with both assays. In 21 cases, the span-assay indicated a BCL6 rearrangement. In 18 of the 21 cases, the dual-color flank-assay confirmed the translocation including 12 different partner chromosomal loci. The three false-positive cases detected with the span-assay showed trisomy of chromosome 3 by cytogenetic analyses, and they were correctly classified as non-rearranged with the flank-assay. In summary, our FISH strategy using two differently labeled flanking BCL6 BAC probes provides a robust, sensitive, and reproducible method for the detection of common and uncommon abnormalities of BCL6 gene in interphase nuclei. The routine application of this assay to patients with B-NHL will allow the assessment of the diagnostic and prognostic significance of BCL6 rearrangements.     

Metallothionein expression correlates with metastatic and proliferative potential in squamous cell carcinoma of the oesophagus

The goal of this study is to clarify whether the expression of metallothionein (MT) could affect the prognosis and the metastatic potential of squamous cell carcinoma (SCC) of the oesophagus. In paraffin-embedded specimens resected from 57 patients, MT mRNA and protein expressions were detected by in situ hybridization and immunohistochemistry respectively. The expression of MT was evaluated in respect of clinicopathologic variables and patients' survival. MT mRNA expression was significantly associated with the proportion of lymph node metastasis (71% in MT mRNA-positive tumours vs 42% in MT mRNA-negative tumours; P = 0.0343) and that of distant metastasis (29% in MT mRNA-positive tumours vs 5% in MT mRNA-negative tumours; P = 0.0452). In respect of MT protein expression, the frequency of distant metastasis was more common in MT-positive tumours than in MT-negative tumours (30% in MT-positive tumours vs 8% in MT-negative tumours; P = 0.0446). The survival rate of the patients with MT protein-negative tumours was significantly better than that of the patients with MT protein-positive tumours (P = 0.0340). There was a positive correlation between the expression of MT protein and that of proliferating cell nuclear antigen (P = 0.0018). Therefore, we conclude that MT expression, both at the mRNA and protein levels, may be a potential marker predicting metastatic and proliferative activities of oesophageal SCC.     

Osteopontin expression correlates with adhesive and metastatic potential in metastasis-inducing DNA-transfected rat mammary cell lines

A metastatic phenotype can be induced in benign rat mammary cells (Rama 37 cells) by transfecting them with metastasis-inducing DNAs (Met-DNAs). Stable transfection of Met-DNAs increases the level of the metastasis-associated protein, osteopontin. Randomly picked clonal cell lines have been established from the pool of Rama 37 cells transfected with one metastasis-inducing DNA, C9-Met-DNA. In these cell lines, moderate correlation is observed between the copy number of C9-Met-DNA and their metastatic potential (linear regression coefficient, R(2)=0.48). A very close correlation is observed between the cell lines' metastatic potential in vivo and the osteopontin mRNA levels in vitro (R(2)=0.74), but not with another metastasis-associated protein in this system, S100A4 (R(2)=0.21). A close correlation is also observed between osteopontin mRNA levels and the adhesive potential (R(2)=0.91) of the cells, but not with their growth rate in vitro (R(2)=0.03). These observations support the previous suggestion that osteopontin is the direct effector of C9-Met-DNA and that the presence of C9-Met-DNA is necessary, if not sufficient, for the induction of metastasis in vivo in this system. Additionally, these results suggest that Rama 37 cells with increased osteopontin mRNA levels become metastatic not through an increased growth rate, but through an increase in cellular adhesiveness.     

Histo-blotting: hybridization in situ detection of specific RNAs on tissue sections transferred on nitrocellulose

A simple and rapid variant of in situ hybridization on tissue sections (histo-blotting) usable for detection of specific RNA distribution among tissues is proposed. Tissue sections prepared with a cryostatic microtome are placed on nitrocellulose and these "histo-blots" are hybridized with labelled DNA or RNA probes under conditions of Northern-blot hybridization without any particular pretreatment. Tissue specificity of the RNA distribution may be determined by comparison of autoradiograms with the histological structure of the stained section. Histological staining and light microscopy may be carried out after hybridization of histo-blots. Hybridization in situ may be easily combined with immunostaining under conditions of immunoblotting. Application of the proposed method is shown for alfa-fetoprotein (AFP) and endogenous provirus (ev-3) RNA detection in rat and chicken embryos, respectively. Histo-blotting results correlate with the distribution of given RNAs among tissues determined by independent methods. Sensitivity, specificity and resolution of histo-blotting have been evaluated and discussed.     

A multicolor fluorescence in situ hybridization assay: A monitoring tool in the surveillance of patients with a history of non-muscle-invasive urothelial cell carcinoma: A prospective study

BACKGROUND:

Non–muscle‐invasive urothelial cell carcinoma (NMIUCC) has a high tendency to recur and affected patients must be monitored regularly using invasive cystoscopies. The aim of the current study was to compare a multicolor fluorescence in situ hybridization (FISH) assay (UroVysion) with routine follow‐up (cystoscopy and cytology) in the monitoring of patients with a previous history of NMIUCC.

METHODS:

An unselected cohort of patients under surveillance for a previous history of NMIUCC was prospectively studied. A total of 248 examinations in 223 patients were analyzed. Each exploration was comprised of cytological and FISH microscopic examination of voided urine samples and cystoscopy. The sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values for tumor recurrence of all 3 techniques were determined.

RESULTS:

The sensitivities of FISH and cystoscopy were not found to be significantly different (92.9% and 82.1%, respectively). The specificities of FISH and cystoscopy were 92.7% and 89.7%, respectively. The PPV and NPV of FISH were 53.5% and 97.2%, respectively, whereas those of cystoscopy were 63.4% and 98.9%, respectively. No significant differences were found between these 2 tests. In contrast, the sensitivity and specificity of cytology were 14.3% and 99.5%, respectively.

CONCLUSIONS:

Given the lack of statistically significant differences with regard to FISH and cystoscopy results, the authors propose that FISH could be a useful monitoring tool in the surveillance of patients with a previous history of NMIUCC. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society.     

Gene amplifications detected by fluorescence in situ hybridization in pure intraductal breast carcinomas: relation to morphology, cell proliferation and expression of breast cancer-related genes

Investigation of early breast carcinogenesis is limited by the difficulty in obtaining cell cultures or adequate fresh frozen material and by the fact that available data from in situ techniques are interpreted in terms of various classification systems. Our studies in a series of pure ductal carcinomas in situ (DCIS) were conducted in accordance with the recommendations of the international Consensus Conference (Hum. Pathol., 28, 122-125, 1997) relative to processing, determination of lesion extent, and histological stratification primarily on nuclear grade (NG). A multifactorial study performed in 15 low- and 16 high-NG DCIS (68% detected by mammography) included the following: (1) morphological analysis of NG, necrosis, and architectural pattern; (2) detection of numerical genomic abnormalities at ERBB2, MYC, CCND1, Xq1.2 and 20q13 loci by fluorescence in situ hybridization on interphase nuclei; and (3) immunohistochemical determination of cell proliferation, p53 accumulation, hormonal receptors and bcl-2 expression on serial sections of formalin-fixed, paraffin-embedded specimens. High NG, comedo/solid pattern and necrosis were significantly associated with amplification at one or more loci, the number of amplified loci, amplification at the ERBB2 locus, absence of bcl-2 and hormonal receptor expression and high cell proliferation (p < 0.05). High NG and comedo/solid pattern were significantly associated with MYC amplification and p53 accumulation, and necrosis with CCND1 amplification (the only gene amplification detected in low NG DCIS). These data provide additional information on the early steps of breast carcinogenesis, in accordance with currently recognized criteria of histological classification.     

新基因1A6定位及在肿瘤中的双色荧光原位杂交分析

目的 了解定位新基因1A6在不同组织来源肿瘤中的状态。方法 用单色FISH法将载于质粒的1A6基因小片段cDNA定位于C组某一染色体长臂,根据该基因测序结果设计8对引物,通过PCR在PAC文库中筛选目的的基因的基因组DNA。用切口翻译法分别用红绿荧光直接标记12号α－卫星重复序列和1A6基因组DNA,采用双色荧光共杂交的方法定位1A6基因,并对其及12号染色体进行了数量分析。结果 1A6基因定位于12q23.2-23.3。1A6基因在乳腺癌、卵巢癌及胃癌细胞株中双色FISH的绿红信号比（R值）为0．96－1．01,在胃癌组织印片中R值为0．93－1．11。12号染色体在乳腺癌细胞株BMI中的双体率87．7％,三体率7．4％;在卵巢癌细胞株SKOV3中的多体率100％,其中五倍体67．6％;在胃癌细胞株BGC823中的多体率为83．1％,其中三体率为71％。在实体瘤胃癌组织印片中,86．4％（19／22）的病例12号染色体以双拷贝为主。结论 1A6基因在实体瘤胃癌组织及肿瘤细胞株（BGC823、SKOV3、BMI）中均无明显扩增和缺失,推测其在肿瘤中的作用方式不是扩增或缺失。12号染色体数目在不同组织来源肿瘤细胞株中各异,意义有待探讨。