Lymphatic metastasis influences clinical treatment and prognosis of patients with non-small-cell lung cancer (NSCLC). There is an urgency to understand the molecular features and mechanisms of lymph node metastasis. We analyzed the molecular features on pairs of the primary tumor and lymphatic metastasis tissue samples from 15 NSCLC patients using targeted next-generation sequencing. The potential metastasis-related genes were screened from our cohort based on cancer cell fraction. After filtering with gene functions, candidate metastasis-related events were validated in the MSK cohort with Fisher’s exact test. The molecular signature and tumor mutational burden were similar in paired samples, and the average mutational concordance was 42.0% ± 28.9%. Its metastatic mechanism is potentially a linear progression based on the metastatic seeding theory. Furthermore, mutated ataxia telangiectasia mutated and Rad3-related (ATR) and tet methylcytosine dioxygenase 2 (TET2) genes were significantly enriched in lymphatic metastases (p ≤ 0.05). Alterations in these two genes could be considered metastasis-related driving events. Mutated ATR and TET2 might play an active role in the metastasis of lymph nodes with NSCLC. More case enrollment and long-term follow-up will further verify the clinical significance of these two genes.

Background: Recurrence cannot be completely prevented by resection or chemotherapy. Molecular biomarkers reported in previous studies have the potential to predict the recurrence risk of lung adenocarcinoma (LUAD), but the results were controversial. Methods: We retrospectively analyzed the molecular characteristics of the 218 early-stage patients with lung adenocarcinoma based on 599 gene-panel target sequencing. All the patients received no neoadjuvant therapy and no EGFR-TKI treatment. The follow-up information on recurrence was complete. Univariate and multivariate analyses were performed using the Cox proportional hazard models to investigate whether the common alterations in EGFR and KRAS were prognostic factors for relapse-free survival(RFS). Results: Among all the enrolled patients, the mutation rates of EGFR and KRAS were 47.6% and 9.3%, respectively. EGFR mutation was not proved to be a prognostics signature of relapse for lung adenocarcinoma regardless univariate and multivariate analysis (univariate: HR, 1.11; 95%CI, 0.82-1.50, P = 0.49; multivariate: HR, 1.18; 95%CI, 0.86-1.64, P = 0.31). The univariate and multivariate analysis identified KRAS alteration as an independent prognostic factor for a shorter RFS (univariate: HR, 1.64; 95%CI, 0.75-2.43, P < 0.05; multivariate: HR, 1.66; 95%CI, 1.19-2.32, P <0.05). For patients in pathological stage I, the patients with KRAS alterations showed significant recurrent risk compared with wild-type patients (HR, 2.02; 95%CI, 1.38-2.96; P <0.0.01). Conclusion: KRAS alterations rather than EGFR alterations were prognostic biomarkers of relapse for early-stage lung adenocarcinoma, especially for patients in pathological stage I. Citation Format: Honggang Ke, Zhongying Jing. The search for molecular biomarkers of relapse in early stage lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1415.

e20511 Background: Lung cancer is the leading cause of cancer-related mortality among the world, and distant metastases is still the main cause of poor prognosis and cancer-related deaths. Lymph nodes nearby primary tumor is the most commonly metastases. More than 90% NSCLC patients were diagnosed at II or higher stage. Although more and more prognosis molecular biomarkers have been identified, it’s still hard to completely understand the metastases mechanism of NSCLC. Here we work on evaluation whether molecular divergence or common mutational characters in matched primary and lymph node metastases of NSCLC could predict patient’s prognosis. Methods: Within MSKCC(MSK-IMPACT-2017) datasets, 12 matched primary and lymph node metastatic samples were gotten. Molecular divergence and similarity were analyzed between matched samples, including SNVs, fusion mutations, CNA, TMB, signature, concordance between primary and metastatic lymph nodes and relate it to patient’s overall survival. Results: Cox survival analysis results proved that the gain of CNA in both primary and lymph node metastases would be a poor prognosis biomarker for NSCLC. 3/3 NSCLC patients with CNA in both primary and metastases occurred death within 10 months, median OS was 7.76 month. Only 1/9 of the others occurred death at 14 months, other NSCLC patients did not reach the end point of this study. HR for OS with CNA in both matched samples versus the others was 0.07 (95% CI 0.0067-0.67), log-rank p value was 0.0028. Conclusions: The gain of CNA in both primary and lymph node metastases could be a poor prognosis predictor for NSCLC patients.

e20517 Background: Metastasis tumor is the leading cause of lung cancer-related deaths, including local metastasis and distant metastasis. Despite its crucial clinical significance, local metastasis of lung cancer is still largely uncharacterized in terms of underlying molecular mechanisms. Here, we performed TSO500 (Illumina, San Diego, CA, USA) sequencing with 19 matched lung cancer primary and local metastatic samples to comprehensively profiling of lung cancer molecular characteristics. Methods: 19 lung cancer patients with paired primary tumor and local metastatic samples were enrolled, including 16 matched primary-lymph node samples and 3 primary-pleura samples. We compared molecular characteristics, including SNV and TMB, of matched samples. Molecular alterations identified were classified into shared (mutations in both primary and metastases) and private (mutations only in primary or metastases) groups. Thus, share mutation statistical analysis, pathway level enrichment and mutational signature was also done. Results: Comprehensively analysis of matched samples showed that mutational concordance between primary tumor and local metastases is lower. The average rate of concordance of primary-lymph node and primary-pleura was 40.6%±28.4%, 39.0%±33.9% respectively. Obviously, no difference in TMB between local metastases and primary tumor was found, average of primary vs lymph node and primary vs pleura was 7.5 vs 6.5, 6.9 vs 4.2 respectively. Significantly, we found that smoking lung cancer patients have higher TMB compared to non-smokers(p < 0.01), regardless primary tumor or metastatic lymph nodes. Conclusions: Lung cancer has higher inter-tumor heterogeneity with proportion of shared mutations less than 50%. Meanwhile, smoking lung cancer has higher TMB in both primary tumor and metastatic lymph nodes compared to non-smokers.