Influence of cytological stains on comparative genomic hybridization analysis for DNA extracted from cytological smears.

In the present study, we investigated the influence of cytological stains in analyzing DNA extracted from cytological slides by comparative genomic hybridization (CGH). Multiple imprint cytological slides were prepared for fresh-frozen breast cancer tissue samples and the slides were stained by three staining methods for each sample. Under microscopic observation, cancer cells were selectively microdissected from the slides and forwarded to DNA extraction, whole genome amplification, and CGH analysis. CGH was successfully performed for all methylgreen-stained and May-Grunwald-Giemsa (MGG)-stained cytological smear slides, but for two Papanicolaou (PAP)-stained slides. The number of chromosomal imbalances detected were 5-10 in methylgreen-stained slides and 5-9 in MGG-stained slides. The chromosomal imbalances resemble each other between methylgreen-stained and MGG-stained slides. The present study indicates that the MGG stain is preferred to the PAP stain for the purpose of cytogenetical analysis by CGH for DNA extracted from cytological smear slides.