Abstract
Genetic analysis using histopathological specimens has been increasing, mainly in cancer genomic medicine. The main target tissue specimens are fixed in formalin, but formalin fixation can cause fragmentation of DNA. In contrast, alcohol-fixed cytological specimens are considered to have good DNA quality, but there is insufficient knowledge of their usefulness in genetic analysis. Therefore, this study was conducted to determine the effectiveness of cytological specimens. In Method 1, the DNA quality of cytological and histopathological specimens and EGFR gene analysis were compared. In Method 2, the effect of aging on the DNA quality of cytological specimens and EGFR gene analysis were investigated. For Method 1, the DNA yield, purity, and integrity value of the cytological specimens were lower than those of the histopathological specimens, but EGFR gene analysis was not different. For RNA analysis, the yield and quality were comparable for cytological and histopathological specimens. For Method 2 the DNA yield and the integrity value were high for specimens stored for less than one year and EGFR gene analysis was successful in specimens stored for more than five years but less than six years. No significant difference was observed for RNA between storage periods. Therefore, cytological specimens stored for less than one year are suitable for genome analysis. In addition, for EGFR gene analysis, cytological specimens stored for more than five years but less than six years are suitable for genome analysis. Therefore, the use of cytological specimens is considered to be appropriate when tissue specimens are difficult to obtain.
