Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. Because of its increased incidence in the last decade and the estimated further increase in the next 2 decades, HCC is arousing great interest. In Europe and North America, it commonly develops on cirrhotic livers, and surveillance programs have therefore been suggested to identify early HCC, at a stage when it remains suitable for surgical therapy and has a better clinical outcome. The only serologic marker used in clinical practice is a-fetoprotein (a-FP), but its sensitivity is poor. In our study, 120 patients with HCC and 90 patients with liver cirrhosis were investigated. We report for the first time to our knowledge that as a marker of HCC, the squamous cell carcinoma (SCCA) antigen has high sensitivity (84.2%) but low specificity (48.9%). However, the combination of a-FP and SCCA yielded a correct serologic diagnosis in 90.83% of the HCC patients. A small percentage of patients remain undetected, likely because of the low specificity of SCCA. In conclusion, the combined use of a-FP and SCCA antigen represents a more powerful tool for the serologic detection of HCC. ' 2005 Wiley-Liss, Inc.Key words: SCCA; HCC; a-fetoprotein; diagnosis; cirrhosis Hepatocellular carcinoma (HCC) is becoming a major health problem worldwide as it represents the fifth most common cancer in the world and the third most common cause of cancer-related death. In Europe and the USA, the incidence rates of HCC have strongly increased in the last decade and will likely increase further in the upcoming 2 decades due to hepatitis C virus infection, 1,2 although there is some controversy as to whether it is directly responsible for liver cancer development. [3][4][5] In Western and North American countries, HCC commonly develops in cirrhotic livers whatever the etiology, so that liver cirrhosis by itself represents the strongest risk factor. 3,5,6 The clinical outcome and the prognosis of HCC are unsatisfactory, even if in developed countries a major improvement of treatment and survival has been achieved in patients with HCC at the initial stage. 7 Therefore, surveillance programs aimed at detecting early stage HCC have been recommended by the European Association for the Study of the Liver (EASL) as well as the Italian Association for the Study of the Liver (AISF). These programs are based on the use of ultrasound tomography and a-fetoprotein (a-FP). The reliability of imaging techniques has greatly improved in the last years but such diagnostic procedures are expensive and subject to interpretation. On the other hand, as the only diagnostic serologic test currently available in clinical practice, a-FP has too low a sensitivity and specificity; based on receiving operating characteristic (ROC) curve analysis, its sensitivity reaches only 60%. 8 It has been reported that the squamous cell carcinoma antigen (SCCA) is overexpressed in HCC tissues. 9 SCCA is a component of the high molecular weight serine protease inhibitors named serpins. 10 A different expressi...