How to prepare cytological samples for molecular testing

Abstract

This review is focused on the challenges in standardising and optimising molecular testing workflow in cytopathology. Although cytological samples yield optimal quality DNA, whose minimal amounts in most cases suffice even for multigene mutational profiling, the success of molecular testing is strongly dependent on standardised preanalytical protocols for maximising DNA yield and quality. Sample cytopreparation influences, even more, the quality of RNA and consequently the potential success of reverse transcription-PCR. Here, the educational and technical involvement of the cytopathologist as a relevant component of a multidisciplinary team, in the issues related to test request, specimen collection, fixation, processing, staining, tumour fraction enrichment, DNA quality/quantity assessment and storage conditions is discussed. In addition, the specific sample requirements related to more recent technological developments are examined, underlining the modern role of the cytopathologist, whose continuous education is crucial to meet the opportunities of molecular medicine.

Keywords: cancer; cell block; cytopathology; direct smear; fine-needle aspiration; molecular cytopathology; mutational analysis; next generation sequencing; personalized medicine; polymerase chain reaction; preanalytic.