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    P1.02 - Poster Session 1 - Novel Cancer Genes and Pathways (ID 144)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P1.02-006 - Identification of targetable driver mutations in molecularly selected never smoker lung adenocarcinomas (ID 2970)

      09:30 - 16:30  |  Author(s): G. Metro

      • Abstract

      Background
      Approximately 25% of lung cancers occur in lifelong never smokers. Although no dominant risk factor has been identified yet, the discover of molecular drivers potentially targetable with biological agents, makes lung cancer in never smokers a unique disease, candidate for a personalized therapy. Through the FISH test, we performed a screening for ALK, ROS1, and RET rearrangements, in a highly selected population of lung adenocarcinoma never smoker patients, previously demonstrated to be wild-type for EGFR and K-RAS mutations.

      Methods
      We collected archived histological material of 28 EGFR and K-RAS wild-type patients (pts), from a 200 never-smoker advanced lung adenocarcinomas database, to be analyzed for the presence of rearrangements in ALK, ROS1 and RET genes. All pts were treated at the Division of Medical Oncology of the S Maria della Misericordia Hospital in Perugia from October 2003 to February 2013. 20 specimens were included in a tissue microarray (TMA) analysis, whereas 8 were screened in separate subset, due to the scarce samples. FISH test was performed using a combination of commercial reagents and custom designed probes. Median overall survival (OS) of mutated pts compared to the pan-negative ones, was evaluated by Cox multivariate analysis.

      Results
      Clinicopathological characteristics: among the 28 patients, 27 were never smokers and 1 former light smoker, with a good performance status; 20 (72%) presented with a metastatic disease at diagnosis, 8 (28%) were locally advanced; median age was 56 years-old, with a predominance of female sex (18/28, 64%). All cases were invasive adenocarcinomas and classified into 18 (64%) solid predominant type, 1 (3.5%) mixed acinar/lepidic pattern, 1 (3.5%) papillary, no predominant subtype for 8 (28%) patients, because of unsufficient histological material available. Of the 28 never smoker cases, we identified 7 gene fusions (25%), including 2 pts ALK+ (7.1%), 3 pts ROS1+ (10.7%) and 2 RET+ cases (7.1%), one compatible with KIF5B:RET and other with CCDC6:RET fusion. Median OS for the entire cohort was 24.5 months (mo), 61.2 mo for mutated pts (any rearrangement) vs 24.1 mo for not-mutated, respectively (P = .292).

      Conclusion
      Molecularly selected never smoker lung adenorcinomas associates with a high incidence of driver genes mutations and further investigations to confirm our frequencies in larger cohorts are needed. In line with literature data, our findings suggest a different survival outcome among genotypes, and identification of specific subsets in this special population can lead to successful treatment with target therapies.

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    P2.06 - Poster Session 2 - Prognostic and Predictive Biomarkers (ID 165)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P2.06-028 - ERCC1 mRNA expression and KRAS mutation status in EGFR wild type (WT) advanced non-small cell lung cancer (NSCLC) patients (ID 2405)

      09:30 - 16:30  |  Author(s): G. Metro

      • Abstract

      Background
      In a previous report of EGFR WT advanced NSCLC patients treated with first-line platinum-based chemotherapy we observed a worse clinical outcome for KRAS-mutants compared with KRAS WT patients (Metro et al. ESMO 2012). Here, we assessed whether this phenomenon could be due to different levels of ERCC1 expression.

      Methods
      From a prospectively maintained database of EGFR WT advanced NSCLC patients diagnosed at a single Institution between January 2006 and November 2012, we identified the individuals who had a known KRAS mutation status and tissue available for assessment of ERCC1 mRNA expression. Total RNA was isolated from paraffin-embedded tumor specimens using RNeasy Mini kit and automatically purified by QiaCube instrument (Qiagen). Quantification of mRNA expression levels of ERCC1 was analyzed by real-time one-step RT-PCR using QuantiFast technology by RotorGeneQ instrument (Qiagen), and the results were compared considering β-actin as the internal reference gene.

      Results
      One hundred and eleven patients were evaluable, 60 of which were KRAS-mutants. Among KRAS-mutants, the rate of codon 12/13/61 mutations were 80%/13.3%/6.7% respectively. Baseline patients characteristics were as follows: median age was 62 years (35-84), 36.9% were male, 63.9% were stage IV, 78.3% were PS 0 or 1, 87.3% were ever-smokers, and 71.1% had received a first-line platinum-based chemotherapy. More ever-smokers were present in the KRAS-mutant subgroup compared with WTs (90% versus 76.5%, respectively, P = 0.08). ERCC1 average scores ranged from 0.1 to 26.7, the values being not normally distributed (Kolmogorov-Smirnov test, P<0.0001). Median and mean overall ERCC1 values for all patients were 1.3 and 2.2 [standard deviation (SD) 3.4], respectively. There was no statistically significant difference in terms of ERCC1 median values betwen KRAS-mutants and KRAS WTs (1.4 vs. 1.3, respectively, P = 0.27). Nevertheless, mean ERCC1 expression levels were found to be significantly higher in KRAS-mutants compared with KRAS WTs [2.9 (SD 4.5) vs. 1.4 (SD 0.8), respectively, P = 0.02]. This finding was due to 7 KRAS-mutant patients (ERCC1 high) coming out with ERCC1 levels higher than 5.0, thus notably incresing mean ERCC1 values. In the group of patients treated with first-line platinum-based chemotherapy (n = 79), median progression-free survival was 1.9 months for KRAS-mutant, ERCC1 high patients (n = 6), 5.1 months for KRAS-mutant, ERCC1 low patients (n = 38), and 7.1 months for KRAS WT patients (n = 35) (P = 0.003).

      Conclusion
      KRAS-mutant NSCLCs may express higher levels of ERCC1 compared with KRAS WTs, which could translate into poor sensitivity to first-line platinum-based chemotherapy. Combination strategies of platinum-based chemotherapy plus KRAS-targeting agents may represent an appealing upfront strategy for KRAS-mutants advanced NSCLCs, particularly in presence of concomitant expression of high ERCC1 levels.