ITIH3 and cancer: By exploiting RNA-sequencing data of over 1,000 cell lines from the Cancer Cell Line Encyclopedia (CCLE) (https://www.broadinstitute.org/ccle), we were able to show that ITIH1-ITIH3 were most strongly expressed in liver cancer cell lines (ITIH4 expression seems to be silenced across all cancer cell lines) (Supplementary Figure 4).