ARMS for EGFR mutation analysis of cytologic and corresponding lung adenocarcinoma histologic specimens

Epidermal growth factor receptor (EGFR) mutation analysis is becoming a routine clinical practice for lung adenocarcinoma patients. Most patients with lung cancer are diagnosed at an advanced stage of the disease and are not suitable for surgical therapy. In many cases, cytologic specimens may be the only tissue available for diagnostic and molecular testing. Therefore, it is important to determine what condition the cytologic specimens should be in for adequately analyzing EGFR mutation status.

Fifty-eight paired cytologic and lung adenocarcinoma histologic specimens that satisfied 3 requisite parameters (>2 ng/μl DNA concentration, >30 tumor cells content, and >25% tumor percentage) were collected. Exons 18 through 21 of the EGFR gene were analyzed by amplification refractory mutations system.

The EGFR mutation concordance rate between cytologic specimens and corresponding histologic specimens was 100%. A set of 30 paired specimens from different sites (lung and pleural fluids) from the same patient exhibited 100% concordance in the EGFR mutation analysis results.

In this study, EGFR mutation presented a convenient and reliable method for the analysis of cytologic specimens that satisfied 3 requisite parameters (>2 ng/μl DNA concentration, >30 tumor cells content, and >25% tumor percentage). We concluded that the specimens from both primary lung adenocarcinomas and metastatic lesions (such as pleural fluids) can be used for EGFR mutation analysis.