Correlation of EGFR and KRAS mutation status, response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors and survival with histologic subtypes of adenocarcinoma of the lung.

7080 Background: We described a classification for adenocarcinoma with a bronchioloalveolar component (Ebright M Ann Thorag Surg 2002; 74:1640)dividing tumors into 3 categories: pure BAC, BAC with invasion, and adenocarcinoma with BAC features. In a series of 100 surgically treated patients characterized in this manner, outcome varied by stage aand clinical pattern but not by histology. Additional studies have shown a correlation of BAC subtype with response to TKIs, the greatest response seen in patients classified as adenocarcinoma with BAC features. Recently a stronger association with response to TKI has been shown for mutations in EGFR. In this study, we analyzed a series of 63 NSCLC patients for EGFR and KRAS mutations, response to TKI, and survival and correlated these findings with histology as above.,NSCLC were classified as pure BAC, adenocarcinoma with BAC features, adenocarcinoma, and poorly differentiated NSCLC. EGFR exons 18-24 and KRAS were sequenced. Response to TKIs was determined using standard criteria. Median survival was calculated by log-rank test.,Median survival differed significantly between patients with tumors showing a BAC component versus those that did not (p=0.02). BAC component did not correlate with EGFR mutation (p=0.19) or KRAS mutation status (p=0.27). There was a trend for BAC presence to be associated with response to TKIs (p=0.09).,The presence of a BAC component is a predictor of survival and may be useful in drug selection for patients whose EGFR mutational status is unknown or cannot be ascertained. [Figure: see text] [Table: see text].