Chromogenic in situ hybridization: a novel approach to a practical and sensitive method for the detection of HER2 oncogene in archival human breast carcinoma

The high incidence of HER2 overexpression on the cell surface of breast cancer cells and the recognized prognostic and potentially predictive value of HER2 render this cell surface receptor a novel and important therapeutic target. Although immunohistochemistry (IHC; HercepTest) and fluorescence in situ hybridization (FISH; PathVysion and INFORM)-both approved by the Food and Drug Administration-have emerged as the most viable assays for evaluation of HER2 status in routine clinical practice, there is still no consensus on which is the best method for assessing HER2 status. Therefore, our specific objective was to establish a chromogenic in situ hybridization (CISH) assay for the detection of HER2 amplification on a cohort of 173 archival invasive breast carcinomas. Results were compared with HercepTest, which is the most frequently used method for detecting HER2 alteration. Additionally, HER2 gene copy number was investigated using differential PCR (dPCR) as a testing system. HER2 overexpression was found by IHC in 24.3%; HER2 amplification was found by CISH in 19.1% and by dPCR in 9.2% of the tumors. The overall concordance rate was 95.9% between CISH and IHC and 85.0% between dPCR and IHC. Kappa statistics revealed an excellent agreement between IHC and CISH (kappa = 0.878), but only a moderate agreement was found between IHC and dPCR (kappa = 0.482). Discrepant cases between CISH and HercepTest and all IHC-positive cases (+2 and +3), a total of 42 cases, were analyzed with the FISH PathVysion (Vysis) assay. Among 25 HercepTest-positive cases (score +3), 2 showed no gene amplification by FISH or CISH. Four of 13 tumors with weak HER2 overexpression (score +2) were negative with both FISH and CISH. Concordance between CISH and FISH was 100% for the 38 cases analyzed. The current study showed that CISH represents a practical and simple assay for evaluating HER2 gene amplification in archival material, offering a promising alternative to IHC or FISH for the routine diagnostic setting.     

Evaluation of the clinical significance of HER2 amplification by chromogenic in situ hybridisation in patients with primary breast cancer

BACKGROUND: The purpose of this study was to assess the clinical relevance of HER2 amplification by a novel chromogenic in situ hybridisation (CISH) technique in patients with primary breast cancer and to determine its relationship with other prognostic markers. MATERIALS AND METHODS: One hundred and seventy-three breast cancer patients with a mean follow-up duration of 75 months were reanalysed in this retrospective study. Expression of HER2 in tumour tissue samples was assessed by immunohistochemistry (IHC) and CISH. Discrepant cases and tumours presenting a HER2 2+ and 3+ staining with IHC were additionally analysed by fluorescence in situ hybridisation (FISH) to exclude false-positive results. RESULTS: HER2 overexpression and amplification was found in 24.3% and 19.1%, respectively. The clinico-pathological correlations revealed a significant association between positive HER2 status and standard prognostic factors including high tumour grade, large tumour size and absence of steroid hormone receptors. Univariate analysis indicated that HER2 overexpression and amplification were predictive for poor overall (OS) and disease-free survival (DFS). The same effect was also seen in the patient groups with node-negative as well as node-positive breast cancer. By multivariate analysis, HER2 alteration proved to be an indicator of poor prognosis, independent of tumour size, tumour grade, hormone receptor expression, nodal involvement and adjuvant therapy. CONCLUSION. HER2 expression, as assessed by CISH, is an independent marker for unfavourable prognosis in primary breast cancers.     

Neuropeptides in human salivary (submandibular and parotid) glands.

The existence, distribution and density of various neuropeptides in human submandibular and parotid glands were investigated using immunocytochemistry and radioimmunoassay. Numerous nerve fibers containing vasoactive intestinal polypeptide (VIP) and peptide histidine methionine (PHM), or neuropeptide Y (NPY) and C-flanking peptide of NPY (CPON) immunoreactivities (ir) were found in close association to acini, ducts and blood vessels. Only few calcitonin gene-related peptide (CGRP)- and substance P (SP)-ir nerve fibers could be demonstrated, mainly localized around blood vessels and ducts. Galanin and the newly discovered peptides helospectin and pituitary adenylate cyclase activating peptide (PACAP) could not be detected in human salivary glands.     

Regulatory peptides in the human soft palate

The distributions of vasoactive intestinal polypeptide, peptide histidine methionine, helospectin, neuropeptide Y and its C-flanking peptide, substance P and calcitonin gene-related peptide were studied in the human soft palate using immunocytochemical techniques. Peptide-containing nerve fibers were found to form a dense network around glandular acini, excretory ducts and blood vessels, as well as beneath and within the epithelium. Chromogranin A, bombesin-flanking peptide and calcitonin gene-related peptide immunoreactivities were detected in endocrine-like cells located in excretory ducts.     

Gangliocytes in neuroblastic tumors express alarin, a novel peptide derived by differential splicing of the galanin-like peptide gene

In neuroblastic tumors a relationship of differentiation of the tumor to galanin receptor expression and antip roliferative and apoptotic effects upon activation of galanin receptors in neuroblastoma cells was reported. To elucidate the expression of other components of the galanin peptide family in neuroblastic tumors, RT-PCR analysis of a variety of human neuroblastic tumor tissues was performed. Ganglioneuroma tissues revealed the presence of a splice variant of the galanin-like peptide (GALP) mRNA, which results in exclusion of exon 3 and a frame shift after the signal peptide sequence of GALP. This generates a peptide of 25 amino acids, which we have termed alarin because of the N-terminal alanine and the C-terminal serine. The novel neuropeptide alarin does not reveal significant homology to other peptides. Immunohistochemistry with antibodies directed against synthetic alarin peptide detected specific cytoplasmic granular staining in ganglia of human ganglioneuroma and ganglioneuroblastoma, as well as differentiated tumor cells of neuroblastoma tissues. Undifferentiated neuroblasts of these tumor tissues did not show alarin-like immunoreactivity and alarin-specific mRNA. Our findings indicate that alarin expression is a feature of ganglionic differentiation in neuroblastic tumor tissues.     

p34cdc2 in invasive breast cancer: relationship to DNA content, Ki67 index and c-erbB-2 expression

Aims : One-hundred and eighty-eight cases of human mammary carcinoma were examined immunohistochemically for their expression of Ki67, p34^cdc2 and c-erbB-2. DNA image cytometry was performed to evaluate DNA ploidy, Auer type, S-phase fraction (SPF), 5c exceeding rate (5cER) and 2c deviation index (2cDI).  

Methods and results

One-hundred and sixty-eight cases were invasive ductal carcinomas, 20 were of invasive lobular type. Routinely assessed oestrogen and progesterone receptor scores were available. The results were analysed statistically in comparison to tumour type, histopathological grade, lymph node status, menopausal status, patient age and overall survival. Ki67 ( P  < 0.002) and c-erbB-2 ( P  < 0.0001) correlated well with overall survival ( P  < 0.0008) and grade ( P  < 0.038) but not with lymph node status and tumour type. p34^cdc2 showed a trend towards a positive correlation with Ki67 ( P  < 0.058) and a significant negative correlation with receptor status ( P  < 0.008) but with none of the other parameters examined.  

Conclusions

No association between the DNA measured parameters (Auer type, SPF, 5cER and 2cDI) and survival was found. Our results suggest that c-erbB-2 and Ki67 are parameters which might, in combination with receptor status, help to define subgroups with different outcomes.     

Nitric Oxide Synthase in the Innervation of the Human Nasal Mucosa: Correlation With Neuropeptides and Tyrosine Hydroxylase

Nitric oxide (NO) is a powerful mediator in the central and peripheral nervous system. In the present study the authors have examined the human nasal mucosa innervation for the presence of the neuronal isoform of the NO-generating enzyme, NO-synthase (NOS), and its correlation with other neuronal mediators and markers by means of double-labeling immunohistochemistry. NOS-immunoreactive nerve fibers were observed to be numerously present around glands and venous sinusoids and, less frequently, around small arteries and veins. Few fibers were seen in the lamina propria. NOS appeared to be frequently colocalized in nerve fibers with vasoactive intestinal peptide and, occasionally, with substance P and tyrosine hydroxylase, a marker for catecholamine biosynthesis. These findings suggest that neurally released NO is an important regulatory mediator of glandular secretion and blood flow in the nasal mucosa.     

Detection of human papillomavirus in cervical carcinoma: comparison of peroxidase, Nanogold, and catalyzed reporter deposition (CARD)-Nanogold in situ hybridization.

We compared three in situ hybridization (ISH) methods for their applicability and sensitivity in detecting human papillomavirus (HPV) in 61 cases (1 Grade 1, 18 Grade 2, 42 Grade 3) of routinely processed squamous cell cervical carcinoma. A commercially available biotinylated probe for HPV-16/18 was applied to serial sections and detected by conventional streptavidin-biotin-peroxidase ISH, streptavidin-Nanogold-silver ISH, and catalyzed reporter deposition (CARD)-Nanogold-gold ISH. The latter method involved signal amplification by peroxidase-catalyzed deposition of biotinylated tyramides at the hybridization sites, followed by detection of accumulated biotin by streptavidin-Nanogold made visible by autometallography. The HPV-16/18 detection rates for the three methods were 39.3, 44.3, and 65.6%, respectively. In all of the three ISH methods, a punctate staining pattern (single or multiple intranuclear spots of variable size), presumably indicating viral integration, was highly predominant among the positive cases. Two of the cases identified as positive by streptavidin-biotinperoxidase ISH were rated negative with streptavidin-Nanogold-silver ISH, whereas six cases that were clearly negative with streptavidin-biotinperoxidase ISH became positively stained with streptavidin-Nanogold ISH. All of these discordant cases were positive by the highly sensitive CARD-Nanogold-gold ISH. In addition, the high detection sensitivity of CARD-Nanogold-gold ISH was confirmed by its ability to detect single copies of HPV-16 in SiHa cells. In general, we found that the intense black reaction product from Nanogold autometallography gave superior contrast to that obtained with the peroxidase system. After tyramide signal amplification, the staining was so clearly visible that preparations could be readily screened under low magnification. Our findings precisely demonstrated the need for improved sensitivity in the in situ detection of HPV. The CARD-Nanogold-gold technology looks promising as a highly sensitive method for routine ISH in molecular pathology.     

Comparison of real-time PCR signal-amplified in situ hybridization and conventional PCR for detection and quantification of human papillomavirus in archival cervical cancer tissue

Archival paraffin-embedded tumor specimens offer a wealth of information for both cancer research and for routine clinical applications. However, the use of formalin-fixed, paraffin-embedded specimens for quantitative real-time PCR is not yet a standard diagnostic method in many laboratories, in particular for the quantification of human papillomavirus (HPV). Particularly high-risk HPV types are involved in almost 100% of the carcinogenesis of cervical cancer. We compared the diagnostic applicability and sensitivity of real-time PCR to that of chromogenic tyramide-signal-amplified in situ hybridization and conventional PCR for the detection of HPV from archival tissue in 164 cases of carcinoma in situ and cervical cancer. Furthermore, we examined whether the viral load of HPV is of prognostic relevance. Our findings indicate that patients in tumor stage I with a lower viral load of HPV type 16 (HPV16; up to 1,000 copies/ng of DNA) had a significantly better survival than HPV 16-negative patients (P = 0.037). We observed a greater sensitivity of both real-time PCR and conventional PCR for the detection of HPV16 and -18 compared to signal amplified in situ hybridization. We found a considerable concordance between HPV16 (kappa = 0.661) and HPV18 (kappa = 0.781) status as measured by real-time PCR and conventional PCR, indicating similar sensitivities. We recognized an inhibitory effect of formalin fixation and paraffin embedding on the evaluation of real-time PCR quantification.