Relationship between EGFR mutations and clinicopathological features of lung adenocarcinomas diagnosed via small biopsies.

AIM We performed this study to evaluate the frequency of epidermal growth factor receptor (EGFR) mutations and their association with the histological subtype of lung adenocarcinoma diagnosed via small biopsy specimens. PATIENTS AND METHODS Three hundred and fifty-nine lung adenocarcinoma specimens were tested for EGFR mutation by a direct sequencing method. In 135 patients, histological subtypes were classified according to the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification. We compared the EGFR mutation frequency by clinicopathological characteristics. RESULTS We detected 135 (37.6%) EGFR mutations and the incidence was highest in women who never smoked (54.6%). With regard to histological subtype, the highest prevalence of EGFR mutation was found in papillary (81.3%), followed by lepidic (70.4%), acinar (58.1%) and solid (28.3%) tumor types. In addition, the expression of thyroid transcription factor-1 was significantly higher in tumors with the EGFR mutation than in those without (p<0.001). CONCLUSION The histological subtype of adenocarcinoma can be predictive of existing EGFR mutation, although the histology was confirmed using only small biopsies.