BACKGROUND AND AIM: Extremely poor prognosis in hepatocellular carcinoma (HCC) 
patients with progressing disease was denoted by vascular invasion. Cytokeratin 
18 (CK18) has been shown to be overexpressed in hepatocellular carcinoma so it 
is a valuable tumor marker; however, its role in vascular invasion is still 
unclear. This study aimed to predict CK18 as a predictive marker for 
macrovascular malignant invasion.
METHODS: The present study was conducted on three groups of patients: group I 
included 91 HCC patients without macrovascular invasion, group II included 34 
HCC patients with radiological evidence of vascular invasion, and group III 
included 110 control individuals subdivided into IIIA as healthy blood donors 
and IIIB as post-HCV cirrhotic patients without HCC.
RESULTS: ROC curve of M30 fragments of CK18 was constructed for discrimination 
between HCC with and without macrovascular invasion. Optimum cutoff value was 
304.5 ng/mL (AUC = 0.997, P < 0.001), sensitivity (100%) and specificity 
(98.8%). Regression analysis was conducted for prediction of macrovascular 
invasion within HCC patients. The following variables: higher levels of AST, 
M30, bilirubin, and AFP, lower levels of serum albumin, larger tumor size, child 
B score, and multiple lesions were associated with vascular invasion in 
univariate analysis. While in multivariate analysis, higher levels of AST and 
bilirubin and elevated levels of M30 and AFP serum were considered independent 
predictors for macrovascular invasion in HCC patients.
CONCLUSION: The present study suggests that increased M30 fragments of CK18 
levels may be useful as a possible marker of early tumor invasiveness.