Young investigator challenge: Validation and optimization of immunohistochemistry protocols for use on cellient cell block specimens

Abstract

BACKGROUND:The objective of the current study was to establish a process for validating immunohistochemistry (IHC) protocols for use on the Cellient cell block (CCB) system. METHODS: Thirty antibodies were initially tested on CCBs using IHC protocols previously validated on formalin-fixed, paraffin-embedded tissue (FFPE). Cytology samples were split to generate thrombin cell blocks (TCB) and CCBs. IHC was performed in parallel. Antibody immunoreactivity was scored, and concordance or discordance in immunoreactivity between the TCBs and CCBs for each sample was determined. Criteria for validation of an antibody were defined as concordant staining in expected positive and negative cells, in at least 5 samples each, and concordance in at least 90% of the samples total. Antibodies that failed initial validation were retested after altera- Although some antibodies subsequently met validation criteria after optimization of conditions, a few continued to demonstrate inadequate immunoreactivity. These findings emphasize the importance of validating IHC protocols for methanolfixed tissue before clinical use and suggest that optimization for alcohol fixation may be needed to obtain adequate immunoreactivity on CCBs. Cancer (Cancer Cytopathol) 2016;124:89-99.

Insulinoma‐associated protein 1 is a sensitive and specific marker of neuroendocrine lung neoplasms in cytology specimens

“…Our second goal was to ascertain whether INSM1 staining in Cellient cell blocks prepared from cytologic samples correlates with corresponding surgical pathology specimens. Prior studies have compared immunohistochemical staining results in Cellient cell blocks and traditional cell blocks . Wagner et al reported identical staining in both types of cell blocks in 53% of cases, although staining in Cellient preparations had a lower intensity in 10% of the stains used.…”

Utilization of ancillary studies in the cytologic diagnosis of respiratory lesions: The papanicolaou society of cytopathology consensus recommendations for respiratory cytology

“…A recent study demonstrated problems with validation in nearly one half of antibodies tested using the Cellient cell block system (fixed in PreservCyt). 9 The antibodies had been previously validated for formalin-fixed, paraffin-embedded specimens. These findings bring into question the utility of methanol-fixed material for ICC and the probable need for revalidation of antibodies when methanol-fixed material is used.…”

“…A recent study has questioned the reliability of the use of immunocytochemistry on methanol-fixed cell block material. 9 …”

Assisting the neurologist in diagnosis of CNS malignancies ‐ Current Possibilities and Limits of Cerebrospinal Fluid Cytology and Immunocytochemistry

“…All the illustration cases are processed this way. Nevertheless, our experience is similar to many other investigators in the necessity to adjust the protocols to the antibody in question and to the cytology material available (Sauter et al., 2016). …”