Effect of liquid‐based cytology fixing solution on immunocytochemistry: Efficacy of antigen retrieval in cytologic specimens

Abstract

Background: Immunocytochemistry (ICC) is an indispensable technique to improve diagnostic accuracy. ICC using liquid-based cytology (LBC)-fixed specimens has been reported. However, problems may arise if the samples are not fixed appropriately.We investigated the relationship between the LBC fixing solution and ICC and the usefulness of antigen retrieval (AR) in LBC specimens.Methods: Specimens were prepared from five types of LBC-fixed samples using cell lines and the SurePath™ method. ICC was performed using 13 antibodies and analyzed by counting the number of positive cells in the immunocytochemically stained specimens.Results: Insufficient reactivity was observed using ICC without heat-induced AR (HIAR) in nuclear antigens. The number of positive cells increased in ICC with HIAR.The percentage of positive cells was lower in CytoRich™ Blue samples for Ki-67 and in CytoRich™ Red and TACAS™ Ruby samples for estrogen receptor and p63 than in the other samples. For cytoplasmic antigens, the percentage of positive cells for no-HIAR treatment specimens was low in the three antibodies used. In cytokeratin 5/6, the number of positive cells increased in all LBC specimens with HIAR, and the percentage of positive cells in CytoRich™ Red and TACAS™ Ruby samples was significantly lower (p < .01). For cell membrane antigens, CytoRich™ Blue samples had a lower percentage of positive cells than the other LBC-fixed samples. Conclusion:The combination of detected antigen, used cells, and fixing solution may have different effects on immunoreactivity. ICC using LBC specimens is a useful technique, but the staining conditions should be examined before performing ICC.

Evaluation of a Novel Fixative Solution for Liquid-Based Cytology in Diagnostic Cytopathology

“…However, as previously mentioned, the effect of every single component in preservative solutions on cellular elements underlines the need of standardizations of the pre-analytical phases in cytological samples. Indeed, for example, the literature shows that alcohol-fixed samples have higher immunoreactivity than those fixed with solutions containing formaldehyde [5,32,34,35]. Similar to other studies [36], this evidence underlines the need for increased standardization and awareness in all of the pre-analytical/analytical steps such as proper collection and preparation of laboratory specimens or adequate fixative/reagent concentrations and technical equipment for every sample treated.…”

Diagnostic utility of immunocytochemistry by using liquid-based cytology (LBC) slides

“…For cell membrane antigens, certain LBC samples had a lower percentage of positive cells. The authors conclude that ICC using LBC specimens is a useful technique, but the staining conditions should be examined before performing ICC [19]. In our study CytoRich Red was used as the fixative for all samples.…”

“…In a recent study the relationship between the LBC (SurePath) fixing solution and ICC and the usefulness of antigen retrieval in LBC specimens of cell lines has been investigated [19]. Insufficient reactivity was observed without heat-induced antigen retrieval in the staining of nuclear antigens.…”