PTGS2 and colon carcinoma: The same group used a partially purified S. bovis S300 fraction representing 12 different proteins and triggered the synthesis of proinflammatory proteins (human interleukin-8 and prostaglandin E2), correlated with the in vitro overexpression of cyclooxygenase-2 in human colon carcinoma cells and in rat colonic mucosa [33].