Morphometric and cytomorphologic characterization of EGFR-mutated cancer cells-comparison between cultured lung cancer cell lines and lung adenocarcinoma clinical samples.

Background: Recently molecular targeting therapies such as inhibition of enzyme activities associated with gene mutations responsible for lung carcinogenesis have been demonstrating promising outcomes, increasing the importance of gene analysis using clinical samples. Cytomorphologic findings with predictive value toward specific gene mutation such as EGFR mutation could be a useful tool to select appropriate gene analyses using limited clinical samples.

Methods: Morphometrical and cytomorphological evaluations were performed in 7 cultured lung cancer cell lines and 51 lung adenocarcinoma clinical samples to identify specific cytomorphologic characterization of EGFR-mutated cancer cells compared to the wild type.

Results: Morphometry demonstrated that the EGFR mutated cell lines had significantly smaller nuclear area and perimeter and more circular nuclei compared to the wild type. In contrast, EGFR-mutated clinical samples had significantly greater nuclear area and perimeter compared to the wild type EGFR samples. There were no clear differences in cytomorphologic parameters assessing nuclear atypicality between EGFR mutated cells and wild type EGFR cells in either cultured cell lines or clinical samples.

Conclusion: Although our study suggested that EGFR mutation may have specific effects on nuclear morphology, no consistent characteristics of EGFR-mutated cells were identified in the clinical samples, probably due to various factors such as different pathologic stages and various incidences of lepidic growth. Further assessment of morphological characterization of EGFR-mutated cells in lung adenocarcinoma is warranted, increasing the number of samples and considering the effects of polyploidy, other gene mutations, pathology stage and tumor subtypes such as lepidic growth. Diagn. Cytopathol. 2016;44:717-724. © 2016 Wiley Periodicals, Inc.