Based on the CLCA4 expression and serum AFP levels, all the HCC patients were divided into different risk subgroups: patients with CLCA4 (+) and AFP ≤ 400 ng/ml (CLCA4+/AFP-) had better OS time; patients with CLCA4 (+) and AFP > 400 ng/ml (CLCA4+/AFP+), or patients with CLCA4 (-) and AFP ≤ 400 ng/ml (CLCA4-/AFP-), had intermediate prognosis; patients with CLCA4 (-) and AFP > 400 ng/ml (CLCA4-/AFP+) were prone to death (Fig. 3A). Here, AFP is linked to hepatocellular carcinoma.