Olika fixeringsmedels påverkan på immuncytokemiskt uttryck av carcinoembryonalt antigen
: Jämförelse mellan formalin och CytoLyt vid cellblockspreparation

Translated title of the thesis: The impact of different fixatives on CEA immunocytochemical expression: Comparison between formalin- and CytoLyt-fixed cell block preparations
  • Dawla Nakdali

Student thesis: Bachelor


Background: Lung cancer is one of the most common types of cancer,
accounting for approximately 12.4% of all cancer cases globally. Adenocarcinoma
is the most prevalent subtype among non-small cell lung cancer. Diagnosis is
conducted through immunohistochemistry and analysis of CEA expression, which
is high in malignant adenocarcinomas. Both formalin and CytoLyt can be used as
fixative for cytological specimens. The aim of this study was to evaluate the
impact of the usage of formalin or CytoLyt fixatives on the expression of the
diagnostic biomarker CEA in pleural fluid from patients with lung
adenocarcinoma. Materials and methods: The project was based on cytological
specimens in the form of pleural fluid from 10 patients with lung adenocarcinoma,
prepared using manual cell block methods. The inclusion criteria for the study
were as follows: 1) Cell block containing at least 100 cells, 2) Only samples from
patients with lung adenocarcinoma, and 3) Only pleural fluid as the specimen.
Each patient sample was divided into two cell block cassettes, one fixed with
formalin and the other fixed with CytoLyt. After fixation and sectioning, the
preparations were stained with CEA using Omnis according to the provided
manual for this automated system. Subsequently, a contrast stain of Hematoxylin
was applied, followed by the application of Tissue-Tek film for examination.
Results: Concordance between formalin and CytoLyt fixation for CEA expression
at different cut-off values was statistically calculated using OPA. At a cut-off of
1%, the OPA was 100%, while at a cut-off of 10%, the OPA was 90%.
Conclusion: There is almost no significant difference in CEA expression between
formalin and CytoLyt fixatives. Intense staining and background over-staining
were observed in CytoLyt during the analysis of CEA expression, which could
affect staining quality and result accuracy.
Date of Award2023-Jun
Original languageSwedish
SupervisorMohammed S. I. Mansour (Supervisor), Tomas Seidal (Supervisor), Kjell Johansson (Supervisor) & Ann-Sofi Rehnstam-Holm (Examiner)

Educational program

  • Bachelor of Science in Biomedical Laboratory Science

University credits

  • 15 HE credits

Swedish Standard Keywords

  • Biomedical Laboratory Science/Technology (30402)

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