Molecular testing in cytology

Abstract

In the era of personalized medicine, molecular testing plays a critical role in patient care. The rapid advance of molecular techniques, especially next‐generation sequencing, makes molecular diagnosis feasible in daily practice. Molecular testing can be used as a valuable ancillary test to increase diagnostic sensitivity and specificity, especially in small biopsy or cytology samples. In addition, molecular testing plays an important role in selecting patients for appropriate treatment by detecting therapeutic and predictive biomarkers in tissue or cytology samples. Molecular studies can be applied in all cytology samples, sometimes with better results than histology. As molecular testing has become essential for patient care and is often requested to be performed in cytology samples, it is critical for cytopathologists to understand the basics of molecular diagnostic methods, indications for molecular testing, and how to best utilize different cytologic samples for this purpose. In this special issue, experts in various areas of cytopathology and molecular pathology review the literature and discuss the basics of molecular techniques and the application of molecular testing in various types of cytology samples. It is our hope that after reading the articles in this special issue, the readers can know better about the possibilities of molecular cytology, a very exciting field of pathology.

Fusion of old and new: Employing touch imprint slides for next generation sequencing in solid tumors

“…This disparity in success rates can be attributed to the inherent qualities of touch imprint slides, which often provide a richer concentration of tumor cells and less contamination from nontumor elements along with little to no delay for fixation, enhancing the accuracy and efficacy of molecular testing. 1,9,15,[19][20][21] Whereas, smear slides, particularly from aspiration biopsies, may have a paucity of tumor cells and a higher proportion of nondiagnostic material, potentially impacting the success rate of molecular analyses. [22][23][24] On the other hand, failure rates as high as 45% have been reported in certain studies 6,[25][26][27][28][29] that primarily used tissue samples rather than cytological specimens.…”

“…where the success rate in our cohort is around 80% (unpublished data). This disparity in success rates can be attributed to the inherent qualities of touch imprint slides, which often provide a richer concentration of tumor cells and less contamination from nontumor elements along with little to no delay for fixation, enhancing the accuracy and efficacy of molecular testing 1,9,15,19–21 . Whereas, smear slides, particularly from aspiration biopsies, may have a paucity of tumor cells and a higher proportion of nondiagnostic material, potentially impacting the success rate of molecular analyses 22–24 .…”