PreservCyt Is an Optimal Fixative that Permits Cytologic and Molecular Analyses of Vitreoretinal Lymphoma Biopsies

ABSTRACT

Purpose: Vitreoretinal lymphoma (VRL) is a potentially fatal intraocular malignancy. Diagnosis is hampered by poor preservation of morphology and DNA/RNA integrity, which precludes adjunctive molecular analysis. We aimed to determine the optimum fixative protocol for VRL biopsies that permits cytology, IHC/flow cytometry and molecular analyses.

Methods: Six fixatives were compared on cultured Pfeiffer cells used as a cellular model. Cells were fixed and evaluated on cellular morphology, antibody staining, DNA/RNA amount and integrity. VRL clinical cases were used as validation and proof-of-concept.

Results: PreservCyt was the best fixative for preserving cellular morphology and high-quality RNA/DNA from vitreous fluid biopsies. Cells from clinical VRL cases fixed with PreservCyt showed adequate cellular morphology and IHC positivity. Sufficient DNA was obtained for IgH clonality and MYD88 mutation detection using remnant cytological fluid.

Conclusions: PreservCyt maintains good morphology and RNA/DNA integrity suggesting that it is a suitable fixative for VRL diagnosis and molecular analysis.

Keywords:

• Fixative protocols
• lymphoma diagnostics
• MYD88
• vitreoretinal lymphoma
• VRL

Acknowledgments

This study was supported by a research collaboration between A. Menarini Biomarkers Singapore Pte Ltd, VisionSave and the Singapore Eye Research Institute. We would like to thank the Department of Anatomical Pathology and cytology for assisting with cytospin preparations and immunohistochemistry analysis. The data presented here form part of patent filed on 21 August 2018 (#10201807097T). The authors would like to thank Insight Editing London for critical review and editing of the manuscript prior to submission.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This work was supported by the VisionSave Singapore National Eye Centre: [Grant Number JTOTHX008210]; A. Menarini Biomarkers Singapore Pte Ltd: [Grant Number JTOTHX008210]; Singapore Eye Research Institute: [Grant Number JTOTHX008210].