PTX3 and cancer: More recently, in a model of chemical carcinogenesis, the lack of PTX3 has been associated with an exacerbated cancer-related inflammation explained by a defect of complement regulation, as indicated by excessive C3 deposition and a higher amount of the highly inflammatory compound C5a in Ptx3-deficient compared to —competent mice (41) In murine models, until now, only one study has associated the alteration of inflammatory control by PTX3 with the susceptibility to K. pneumoniae infections (16).