PTGS2 and cancer: Siyang et al. 18 found that the abundance of Streptococcus in cancer tissues was higher than that in adjacent non-cancerous ones and Streptococcus could aggravate the tumor microenvironment and accelerate the development of CRC with inflammatory factors such as cyclooxygenase-2 (COX-2), interleukin-1, and interleukin-8.