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Updated: May 22, 2026
Determination of Protein Expression Level in Cultured Cells by Immunocytochemistry on Paraffin-embedded Cell Blocks
Published on: May 20, 2018
Comparison of breast carcinoma prognostic/predictive biomarkers on cell blocks obtained by various methods: Cellient,
Blythe K Gorman1, Ognjen Kosarac, Subhendu Chakraborty
1Department of Pathology and Genomic Medicine, The Methodist Hospital, Houston, TX 77030, USA. bkgorman@tmhs.org
Objective:
To compare results of immunohistochemical (IHC) assays for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) performed on thrombin, formalin and Cellient cell blocks to those performed on tissue.
Study Design:
Formalin, thrombin and Cellient cell blocks were prepared from cytologic samples obtained from resection specimens of 31 patients with invasive breast carcinoma. ER, PR, HER2 and MIB-1 (Ki-67) IHC stains were performed on all three types of cell blocks and compared to the same stains performed on the patient's paraffin-embedded biopsy or resection. Cell and tissue blocks with equivocal staining for HER2 were submitted for fluorescence in situ hybridization (FISH).
Results:
Adequate Cellient blocks were obtained for all 31 cases. Comparison of results of ER IHC assays on all three types of cell blocks showed 100% correlation with tissue. Both Cellient and thrombin blocks showed 100% correlation with tissue for HER2 IHC and FISH results. The only statistically significant difference between cell block methods was found in PR staining, where false-negative results occurred with Cellient and thrombin blocks.
Conclusion:
Breast biomarker IHC assays performed on Cellient blocks are reliable and correlate with tissue block results, particularly for ER and HER2, the most clinically important markers.
