APOB and cholangiocarcinoma: In recent years, some studies have indicated that preoperative PLT to ALB ratio (PAR), PLT to lymphocyte ratio (PLR), LDL-C to HDL-C ratio (LDL-C/HDL-C), and ApoB to ApoA1 ratio (ApoB/ApoA1) were negatively correlated with the prognosis of cholangiocarcinoma [23], lung cancer [24], colorectal cancer [25], and gastric cancer [26], respectively.