Predictive Significance of KRAS and Tau for Chemoresponse in Advanced Non-Small-Cell Lung Cancer

Background : Taxane-platinum combinations are often used as first-line treatments for patients with advanced non-small cell lung cancer (NSCLC). Response to chemotherapy for these patients is still poor. The aim of our study was to investigate, for this disease, whether KRAS and Tau proteins affect responses to taxane-platinum combinations. Methods : Expression of KRAS and Tau was examined immunohistochemically in 71 tumor samples obtained from patients with stage IIIB or IV NSCLC prior to combination therapy. Expression was correlated with tumor responses. Results: The response rate was 55% (39 of 71). KRAS and Tau were expressed in seven (10%) and 31 (44%) patients, respectively. All seven KRAS-positive patients were non-responders (p=0.014). Among Tau-positive patients, 35% (11 of 31) responded to therapy, whereas a partial response was observed in 70% (28 of 40) of Tau-negatives (p= 0.045). Two were positive for both, and they were non-responders. In patients negative for both, the response rate was 71% (25 of 35) (p=0.012). Conclusions: Expression of KRAS and Tau are significantly correlated with poor responses to this combination therapy in advanced NSCLC patients, and may be a useful marker for chemoresistance.