Cell-Cycle and DNA-Damage Response Pathway Is Involved in Leptomeningeal Metastasis of Non–Small Cell Lung Cancer

Purpose: Leptomeningeal metastasis (LM) is a detrimental complication of non–small cell lung cancer (NSCLC) and associated with poor prognosis. However, the underlying mechanisms of the metastasis process are still poorly understood. Experimental Design: We performed next-generation panel sequencing of primary tumor tissue, cerebrospinal fluid (CSF), and matched normal controls from epidermal growth factor receptor ( EGFR ) mutation-positive NSCLC patients with LM. Results: The status of EGFR -activating mutations was highly concordant between primary tumor and CSF. PIK3CA aberrations were high in these patients, implicating an association with LM risk. Intriguingly, low overlapping of somatic protein-changing variants was observed between paired CSF and primary lesions, exhibiting tumor heterogeneity and genetic divergence. Moreover, genes with CSF-recurrent genomic alterations were predominantly involved in cell-cycle regulation and DNA-damage response (DDR), suggesting a role of the pathway in LM development. Conclusions: Our study has shed light on the genomic variations of NSCLC-LM, demonstrated genetic heterogeneity and divergence, uncovered involvement of cell-cycle and DDR pathway, and paved the way for potential therapeutic approaches to this unmet medical need. Clin Cancer Res; 1–8. ©2017 AACR.