TTR and hepatocellular carcinoma: Given that serum cf-QSOX1 was found to be comprised of the QSOX1-S isoform, and was found to be significantly correlated with TTR in HCC patients, we attempted to analyze a potential association of QSOX1-S in tumor tissues with TTR and OS of HCC patients in the subgroup only with type II QSOX1 immunostaining (n = 105) from cohort B. As shown in Supplemental Fig. S8B, the QSOX1 density in this subgroup of type II staining was also found to be significantly associated with OS and TTR in HCC patients.