Exploring Brain Genoarchitecture by Single and Double Chromogenic In Situ Hybridization (ISH) and Immunohistochemistry (IHC) on Cryostat, Paraffin, or Floating Sections

BACKGROUND: In patients with breast cancer, HER2 gene expression is of a great importance in reacting to Herceptin treatment. To evaluate this event, immunohistochemistry (IHC) has been done routinely on the basis of scoring it and so the patients were divided into 4 groups. Lately, as there have been disagreements about how to treat score 2 patients, chromogenic in situ hybridization (CISH) and florescence in situ hybridization (FISH) are introduced. Since CISH method is more convenient than FISH for gene amplification study, FISH has been substituted by CISH. AIM: The current study is conducted in order to investigate whether using CISH is a better method comparison to IHC method for determines HER2 expression in patients with breast cancer in. METHODS: In this cross-sectional descriptive analytical study, information of 44 female patients with invasive ductal breast cancer were gathered from Imam Reza and Omid Hospital in Mashhad. IHC staining was done for all patients in order to determine the level of HER2 expression, and after scoring them into 4 groups of 0, +1, +2 and +3, CISH staining was carried out for all 4 groups. At the end, results from both methods were statistically evaluated using SPSS software V.22.0. RESULTS: The average age of patients was 50.2 with the standard deviation of 10.96. Using IHC method was observed that 2.6% (1 patient), 26.3% (10 patients), 65.8% (25 patients) and 5.3% (2 patients) percentage of patients had scores of 0, +1, +2 and +3. On the other hand, CISH method showed 36 patients (90%) with no amplifications and 4 (10%) with sever amplifications. In a comparative study using Fisher's exact test (p = 0.000), we found a significant relation between IHC method and CISH method indicating that all patients showing severe amplifications in CISH method, owned scores of +2 and +3 in IHC method. CONCLUSION: According to the present study and comparing the results with similar previous studies, it can be concluded that CISH method works highly effective in determining HER2 expression level in patients with breast cancer. This method is also able to determine the status of patients with score +2 in IHC for their treatment with herceptin

Download Full-text

Influence of prolonged formalin fixation of tissue samples on the sensitivity of chromogenic in situ hybridization

Journal of Veterinary Diagnostic Investigation ◽

10.1177/1040638711425584 ◽

2011 ◽

Vol 23 (6) ◽

pp. 1212-1216 ◽

Cited By ~ 10

Author(s):

Meike M. Mostegl ◽

Barbara Richter ◽

Nora Dinhopl ◽

Herbert Weissenböck

Keyword(s):

In Situ Hybridization ◽

Nucleic Acid ◽

Signal Intensity ◽

Formalin Fixation ◽

Proteinase K ◽

Cross Linking ◽

Fixation Time ◽

Tissue Samples ◽

Chromogenic In Situ Hybridization

Chromogenic in situ hybridization (ISH) is a commonly used tool in diagnostic pathology to detect pathogens in formalin-fixed, paraffin-embedded (FFPE) tissue sections. Prolonged formalin fixation time was identified to be a limiting factor for the successful detection of nucleic acid from different pathogens, most probably due to the cross-linking activity of formalin between RNA, DNA, and proteins. Therefore, in the current study, the influence of formalin fixation time on ISH signal intensity of 2 viral ( Porcine circovirus-2 [PCV-2] and Porcine respiratory and reproductive virus [PRRSV]) and 2 protozoal agents ( Cryptosporidium serpentis and Tritrichomonas sp.) was evaluated. Tissue samples were fixed in 7% neutral buffered formaldehyde solution, and at defined intervals, pieces were embedded in paraffin wax and subjected to pathogen-specific ISH. For all 4 pathogens, the signal intensity remained comparable with the starting ISH signal for different periods of fixation (PCV-2: 6 weeks, PRRSV: 23 weeks, C. serpentis: 55 weeks, Tritrichomonas sp.: 53 weeks). Thereafter, the signal started to decline until loss of nucleic acid detection. The influence of increased proteinase K concentrations for inverting the formalin-induced cross-linking activity was examined compared with the standard protocol. With all 4 infectious agents, a 4-fold proteinase K concentration restored the ISH signals to a level comparable with 1 day of fixation. In conclusion, the influence of prolonged formalin fixation on the intensity of detected ISH signal highly depends on the analyzed infectious agent and the pretreatment protocol.

Download Full-text