Whole Blood Gene Expression Profiling in patients undergoing colon cancer surgery identifies differential expression of genes involved in immune surveillance, inflammation and carcinogenesis.

INTRODUCTION: Cancer surgery may represent a potential risk of enhanced growth and metastatic ability of residual cancer cells due to post-operative immune dysfunction. This study identifies changes in transcription of genes involved in immune surveillance, immune suppression and carcinogenesis in the post-operative period of laparoscopic colon-cancer surgery within an ERAS regime.

METHODS: Patients undergoing elective, curatively intended laparoscopic surgery for colon cancer stage I-III UICC were included in the study. Patients followed standard of care in an ERAS setting. Whole blood gene expression profiling (WBGP) was performed on the day prior to surgery and 1, 2, 3 and 10-14 days after surgery. Samples were collected in Paxgene tubes and Labeled cDNA was fragmented and hybridized to Affymetrix GeneChip™ 2.0. Results were corrected for multiple hypothesis testing using the false discovery rate. Pathway analysis was performed through the Molecular Signature Database. Paired fold changes of gene expression were calculated for post-operative compared to pre-operative samples. A mixed effect model was used to test differential gene expression by repeated-measures ANOVA.

RESULTS: WBGP of 33,804 genes at five timepoints in six patients showed 302 significantly differentially expressed genes between samples from the day prior to surgery and the day after surgery. Pathway gene enrichment analysis showed a downregulation of immunologically relevant pathways. There was a significant downregulation of genes involved in T-cell receptor signaling, antigen presentation and NK-cell activity after surgery. Furthermore, there was an upregulation of cytokines related to metastatic ability, growth and angiogenesis.

CONCLUSION: Whole blood gene expression profiling revealed dysregulation of genes involved in immune surveillance, inflammation and carcinogenesis, after laparoscopic colon cancer surgery.