AIM: Platelet-activating factor (PAF) is a pro-inflammatory and angiogenic lipid mediator. Here we aimed to investigate levels of PAF, lyso-PAF (the PAF precursor), phospholipase A2 (PLA2, the enzymatic activity generating lyso-PAF), acetylhydrolase activity (AHA, the PAF degrading enzyme) and PAF receptor (PAF-R) transcripts in cirrhotic liver and hepatocellular carcinoma (HCC). METHODS: Twenty-nine patients with HCC were enrolled in this study. Cirrhosis was present in fourteen patients and seven had no liver disease. Tissue PAF levels were investigated by a platelet-aggregation assay. LysoPAF was assessed after its chemical acetylation into PAF. AHA was determined by degradation of [3H]-PAF. PLA2 levels were assessed by EIA. PAF-R transcripts were investigated using RT-PCR. RESULTS: Elevated amounts of PAF and PAF-R transcripts 1 (leukocyte-type) were found in cirrhotic tissues as compared with non-cirrhotic ones. Higher amounts of PAF and PAF-R transcripts 1 and 2 (tissue-type) were found in HCC tissues as compared with non-tumor tissues. PIA2, lyso-PAF and AHA levels were not changed in cirrhotic tissues and HCC. CONCLUSION: While the role of PAF is currently unknown in liver physiology, this study suggests its potential involvement in the inflammatory network found in the cirrhotic liver and in the angiogenic response during HCC. AIM: Platelet-activating factor (PAF) is a pro-inflammatory and angiogenic lipid mediator. Here we aimed to investigate levels of PAF, lyso-PAF (the PAF precursor), phospholipase A2 (PLA2, the enzymatic activity generating lyso-PAF) METHODS: Twenty-nine patients with HCC were enrolled in this study. Cirrhosis was present in fourteen patients (AHA, the PAF degrading enzyme) and PAF receptor (PAF-R) transcripts in cirrhotic liver and hepatocellular carcinoma and seven had no liver disease. Tissue PAF levels were investigated by a platelet-aggregation assay. LysoPAF was assessed after its chemical acetylation into PAF. AHA was determined by degradation of [3H] -PAF. PLA2 levels were assessed by EIA. PAF- RESULTS: Elevated amounts of PAF and PAF-R transcripts 1 (leukocyte-type) were found in cirrhotic tissues as compared with non-cirrhotic ones. Higher amounts of PAF and PAF-R transcripts 1 and 2 (tissue-type) wer PIA2, lyso-PAF and AHA levels were not changed in cirrhotic tissues and HCC. CONCLUSION: While the role of PAF is currently currently unknown in liver physiology, this study suggests its potential involvement in the inflammatory network found in the cirrhotic liver and in the angiogenic response during HCC.