<p>Supplementary Figure 4. Heatmap of mRNA expression for clustered protocadherin gene families. A. gamma cluster and B. beta cluster in 178 TCGA lung squamous cell carcinomas and 5 MSKCC brain metastasis samples. Yellow ticks under the dendrogram indicate the brain metastasis samples.</p>
ARTICLE ABSTRACT
Large-scale genomic characterization of squamous cell lung cancers (SQCLC) has revealed several putative oncogenic drivers. There are, however, little data to suggest that these alterations have clinical relevance. We performed comprehensive genomic profiling (including next-generation sequencing) of 79 stage IV SQCLCs and analyzed differences in the clinical characteristics of two major SQCLC subtypes: FGFR1 amplified and PI3K aberrant. Patients with PI3K-aberrant tumors had aggressive disease marked by worse survival (median overall survival, 8.6 vs. 19.1 months, P < 0.001), higher metastatic burden (>3 organs, 18% vs. 3%, P = 0.025), and greater incidence of brain metastases (27% vs. 0% in others, P < 0.001). We performed whole-exome and RNA sequencing on paired brain metastases and primary lung cancers to elucidate the metastatic process to brain. SQCLC primaries that gave rise to brain metastases exhibited truncal PTEN loss. SQCLC brain metastases exhibited a high degree of genetic heterogeneity and evidence of clonal differences between their primary sites.Significance: We performed next-generation sequencing of metastatic SQCLCs and primary lung–brain metastasis pairs, identifying PI3K-aberrant tumors as an aggressive subset associated with brain metastases. We identified genetic heterogeneity between lung primaries–brain metastases as well as clonal populations that may highlight alterations important in the metastatic process. Cancer Discov; 5(6); 610–21. ©2015 AACR.This article is highlighted in the In This Issue feature, p. 565
