A simple approach to single-cell microdissection and molecular analysis

OBJECTIVE: To develop a simple approach to single-cell microdissection from Papanicolaou-stained smears and to determine its usefulness in molecular diagnosis using archival cytologic materials. STUDY DESIGN: Culture cells from three cell lines (TT, A549 and Lu65) were used to prepare Papanicolaou-stained smears. Mount-Quick, a mounting medium, was used to establish the method of sorting target single cells from smear slides under direct microscopic observation. Calcitonin receptor gene and codon 12 of the K-ras oncogene were amplified to check the application of single-cell genetic analysis in cytology. RESULTS: The target single cell could be simply sorted from Papanicolaou-stained smears using the Mount-Quick microdissection technique. Boiling in water tuns more suitable for preparing DNA from a single cell or from fewer than five cells versus other methods. Analysis of calcitonin receptor gene and K-ras codon 12 demonstrated that molecular analysis was applicable to a single cell or a few cells from archival Papanicolaou-stained smears. CONCLUSION: This approach has significant implications for cytology: (1) it circumvents the limitations of molecular analysis in cytology and makes the combination of molecular analysis and morphologic diagnosis possible in cases with limited materials; (2) the remaining part of the smear is still preserved well for additional analysis; and (3) the approach is simple, economical and practical for cytology as well as histology.