PTGDR and hepatitis B virus infection: Furthermore, we observed that when exosomal LUCAT‐1, exosomal EGFR‐AS‐1, serum AFP, and serum DCP were combined, it not only distinguished early stage HCC patients from patients with other digestive system tumors but also differentiated early stage HCC patients from patients with precancerous lesions (hepatitis B infection or liver cirrhosis).