Tubuline, BRCA1, ERCC1, Abraxas, RAP80 mRNA expression, p53/p21 immunohistochemistry and clinical outcome in patients with advanced non small-cell lung cancer receiving first-line platinum-gemcitabine chemotherapy

Background: The aim of this study was to assess the predictive value of tumor expression of nine genes on clinical outcome in patients with advanced NSCLC receiving platinum-gemcitabine chemotherapy. Methods: Quantitative PCR or immunohistochemistry were used to analyze the expression of β-tubuline IIA (TUBB2A), β-tubuline III (TUBB3), BRCA1, ERCC1, Abraxas (ABRX) and RAP80 in mRNA isolated from paraffin-embedded tumor biopsies of 45 NSCLC patients treated as part of a larger observational trial. All patients received first-line platinum-gemcitabine chemotherapy for stage IIIB or IV NSCLC. Results: Median progression-free survival (PFS) was 7 months, overall survival (OS) 12 months. A partial treatment response was found in 14 patients (33%). Patients with low ERCC1 or ABRX expression had a significantly better response to chemotherapy (R= -0.45, p< 0.01 for ERCC1; R= -0.40, p= 0.016 for ABRX). A significant correlation was found between the individual time for PFS and the expression of both ERCC1 (R= -0.36, p= 0.015) and ABRX (R= -0.46, p= 0.001). Patients with low ERCC1 expression had a longer OS as compared to patients with high ERCC1 expression (HR = 0.26, log-rank p= 0.02). Conclusions: The study confirms tumor expression of ERCC1 as a predictor for clinical outcome in patients with advanced NSCLC receiving platinum-based chemotherapy, and found ABRX expression to be similarly predictive of clinical outcome. Prospective validation is warranted and - if confirmed - non platinum-containing chemotherapy should be explored as the preferred treatment in patients with high ERCC1 or ABRX expression and no activating mutations of EGFR.