Component with abundant immune-related cells in combined hepatocellular cholangiocarcinoma identified by cluster analysis.

Combined hepatocellular cholangiocarcinoma (cHCC-CCA) is a heterogeneous tumor sharing histological features with hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). The tumor immune microenvironment (TIME) of cHCC-CCA is unclear. We compared the TIME of cHCC-CCA with that of HCC and iCCA. Twenty-three patients with cHCC-CCA after hepatectomy were evaluated in this study. Twenty-three patients with iCCA and HCC were also included. iCCA was matched for size, and HCC was matched for size and hepatitis virus infection with cHCC-CCA. Immune-related cells among the iCCA-component of cHCC-CCA (C-com), HCC-component of cHCC-CCA (H-com), iCCA, and HCC were assessed using multiplex fluorescence immunohistochemistry. Among C-com, H-com, iCCA, and HCC, multiple comparisons and cluster analysis with k-nearest neighbor algorithms were performed using immunological variables. Although HCC had more T lymphocytes and lower PD-L1 expression than iCCA (P < 0.05), there were no significant differences in immunological variables between C-com and H-com. C-com tended to have more T lymphocytes than iCCA (P = 0.09), and C-com and H-com had fewer macrophages than HCC (P < 0.05). In cluster analysis, all samples were classified into two clusters: one cluster had more immune-related cells than the other, and 12 of 23 H-com and eight of 23 C-com were identified in this cluster. The TIME of C-com and H-com may be similar, and some immunological features in these components were different from those in HCC and some iCCA. Cluster analysis identified components with abundant immune-related cells in cHCC-iCCA.