CD99 and neoplasm: In terms of differential expression at the transcriptomics level, increased expression of YWHAZ, ACTB, F-actin-capping protein subunit β (CAPZB), the keratins 8 (KRT8) and 19 (KRT19), the collagen chains α-1(I), α-1(III) (COL3A1), α-2(I) (COL1A2), α-2(V) (COL5A2), osteopontin (SPP1) and KLK6, and decreased expression of HBA1, HBB, ITIH2, ITIH4, ALB, kininogen-1 (KNG1), collagen chain α-6(VI) (COL6A6), CD99 and CD99 antigen-like protein 2 (CD99L2), was identified in the CCA tumor tissue compared to paired non-tumor tissue and tissue from benign liver lesions or normal bile ducts.