Positron Emission Tomography 18F-Fluorodeoxyglucose Uptake Correlates with KRAS and EMT Gene Signatures in Operable Esophageal Adenocarcinoma.

BACKGROUND: 18F-fluorodeoxyglucose positron emission tomography is an imaging modality critical to the diagnosis and staging of esophageal cancer. Despite this, the genetic abnormalities associated with increased 18F-fluorodeoxyglucose (FDG)-maximum standardized uptake value (SUVmax) have not been previously explored in esophageal adenocarcinoma. MATERIALS AND METHODS: Treatment-naïve patients, for whom frozen tissue and 18F-fluorodeoxyglucose positron emission tomography data were available, undergoing esophagectomy from 2003 to 2012, were identified. Primary tumor FDG-uptake (SUVmax) was quantified as low (<5), moderate, or high (>10). Genome-wide expression analyses (e.g., microarray) were used to examine gene expression differences associated with FDG-uptake. RESULTS: Eighteen patients with stored positron emission tomography data and tissue were reviewed. Overall survival was similar between patients with high (n = 9) and low (n = 6) FDG-uptake tumors (P = 0.71). Differences in gene expression between tumors with high and low FDG-uptake included enriched expression of various matrix metalloproteinases, extracellular-matrix components, oncogenic signaling members, and PD-L1 (fold-change>2.0, P < 0.05) among the high-FDG tumors. Glycolytic gene expression and pathway involvement were similar between the high- and low-FDG tumor subsets (P = 0.126). Gene ontology analysis of the most differentially expressed genes demonstrated significant upregulation of gene sets associated with extracellular matrix organization and vascular development (P < 0.005). Gene set enrichment analysis further demonstrated associations between FDG-uptake intensity and canonical oncogenic processes, including hypoxia, angiogenesis, KRAS signaling, and epithelial-to-mesenchymal transition (P < 0.001). Interestingly, KRAS expression did not predict worse survival in a larger cohort (n = 104) of esophageal adenocarcinomas (P = 0.64). CONCLUSIONS: These results suggest that elevated FDG-uptake is associated with a variety of oncogenic alterations in operable esophageal adenocarcinoma. These pathways present potential therapeutic targets among tumors exhibiting high FDG-uptake.

18F-FDG PET intensity correlates with a hypoxic gene signature and other oncogenic abnormalities in operable non-small cell lung cancer.

BACKGROUND: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is critical for staging non-small-cell lung cancer (NSCLC). While PET intensity carries prognostic significance, the genetic abnormalities associated with increased intensity remain unspecified. METHODS: NSCLC samples (N = 34) from 1999 to 2011 for which PET data were available were identified from a prospectively collected tumor bank. PET intensity was classified as mild, moderate, or intense based on SUVmax measurement or radiology report. Associations between genome-wide expression (RNAseq) and PET intensity were determined. Associations with overall survival were then validated in two external NSCLC cohorts. RESULTS: Overall survival was significantly worse in patients with PET-intense (N = 11) versus mild (N = 10) tumors (p = 0.039). Glycolytic gene expression patterns were markedly similar between intense and mild tumors. Gene ontology analysis demonstrated significant enhancement of cell-cycle and proliferative processes in FDG-intense tumors (p<0.001). Gene set enrichment analysis (GSEA) suggested associations between PET-intensity and canonical oncogenic signaling pathways including MYC, NF-κB, and HIF-1. Using an external cohort of 25 tumors with PET and genomic profiling data, common genes and gene sets were validated for additional study (P<0.05). Of these common gene sets, 20% were associated with hypoxia or HIF-1 signaling. While HIF-1 expression did not correlate with poor survival in the NSCLC validation cohort (N = 442), established targets of hypoxia signaling (PLAUR, ADM, CA9) were significantly associated with poor overall survival. CONCLUSIONS: PET-intensity is associated with a variety of oncogenic alterations in operable NSCLC. Adjuvant targeting of these pathways may improve survival among patients with PET-intense tumors.