Chronic inflammation may be linked to tumor beginning since it was shown that there were many inflammatory cells in tumor biopsy samples.306,307 This is true for gastric and colon cancer.308 This is because oncogene activation or chronic inflammation (from infection or exposure to irritants) may trigger the production of pro-inflammatory transcription factors, including NF-κB, STAT3, and HIF-1α. This evidence concerns the gene HIF1A and infection.