1284P - HOXA-related long non-coding RNAs impact prognosis in early stage NSCLC patients

Abstract

Background: HOX genes, grouped in four clusters in humans (HOXA-D), encode for transcription factors that are master regulators of embryonic development and oncogenesis. HOXA cluster, located in chromosome 7, play a critical role in the patterning of tissues with mesodermal components such as lungs. Long non-coding RNAs (lncRNAs) are especially abundant in the HOXA cluster (HOXA10-AS, HOXAS2, HOXAS3, HOXA11-AS, HOTAIRM1 and HOTTIP). We aimed to evaluate the prognostic role of HOXA-related lncRNAs in early stage non-small cell lung cancer (NSCLC). Methods: 100 early stage NSCLC patients resected in our center from June 2007 to November 2013 were studied. Patient characteristics: median age, 65 (32-84); 78% males; 74% stage I; 56% ADK; 23% received adjuvant treatment. With a mean follow-up of 28.7 months, 31% relapsed. As validation data set 200 NSCLC patients from TCGA Research Network were used (RNAseq data). Only stage I-II TCGA samples without prior malignancy or synchronous cancer that not received neoadjuvant treatment were included. Statistical analysis was performed using R and TANRIC. Results: HOTTIP and HOXA11AS impacted prognosis in our cohort of patients. HOTTIP was expressed in all samples and patients with high levels of HOTTIP had shorter TTR (78.3 vs 58 months; p = 0.048) and shorter OS (81.2 vs 61 months; p = 0.023). HOTTIP was overexpressed in SCC (p = 0.007) and in smokers (p = 0.018). HOXA11AS was expressed only in 9% of patients but the patients expressing HOXA11AS had shorter TTR (73.5 vs 32 months; p = 0.002). In the multivariate analysis HOXA11AS emerged as an independent prognostic marker for TTR (OR: 3.13, 95%CI: 1.3-7.3; p = 0.009), while HOTTIP (OR: 2.357, 95%CI: 1.1-5.2; p = 0.036) and age>65 (p = 0.022) for OS. In the validation data set HOXA11AS was validated as prognostic marker (p = 0.019). HOXA11AS expression correlated positively with development genes HOXA11, HOXA13, HOXA10, HOXA9, HOXA3, FOXD1, ZIC5 and miR-196b (HOXA cluster miRNA) and negatively with surfactant metabolism genes SFTPB and NAPSA or let-7a(p < 0.001). Interestingly, the high expression was associated to patients harboring RTN1 mutations (p < 0.0001). Conclusions: HOXA11AS expression in early stage NSCLC patients is a high-risk relapse marker. Legal entity responsible for the study: University of Barcelona, Barcelona, Spain Funding: None Disclosure: All authors have declared no conflicts of interest. Keywords: HOTTIP, NSCLC, lncRNA, HOXA11AS