Please remember that this is a study not the ads and pop-sci articles usually posted here. That means it’s meant to elucidate at most some biological pathways and not to present an overall recommendation. Maybe creatine has strong anti-tumor activity through one pathway and strongly tumor-promoting impacts elsewhere.

Please… just read it as the isolated and interesting insight into biology that it is. It’s a fascinating in vitro result that shows a potentially important role for creatinine in a certain immune response.