Introduction

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary malignant liver cancer, which accounts for ~10% of all such cancers [1, 2]. The prognosis of patients with ICC is poor. Nearly 70% of patients with ICC are already unresectable at the time of diagnosis. Even in patients undergoing curative surgical treatment, the 5-year overall survival (OS) rate is ~30%, and the 5-year recurrence rate is up to 70% [3]. Therefore, effective systemic therapy during the course of the disease is required for the ICC. The combination of gemcitabine and cisplatin is the current first-line therapy for patients with unresectable ICC, but its efficacy remains very limited [4, 31].

RIP-seq or RIP-qPCR

HuCC-T1 and HCCC-9810 Cells were seeded in a 150-mm dish at a density of 1 × 106 cells/ml. The cells were harvested in lysis buffer. The anti-YTHDF2 antibody was used for immunoprecipitated in a dilution of 1:100. The RNA of input and immunoprecipitated samples were isolated with the TRIzol reagent and subjected to sequencing using Illumina HiSeq 2500 platform supplied by Novogene or qPCR analysis. For qPCR analysis, a flank region with no signal was used as a negative control.

Statistical analysis

The statistical analysis of the data was carried out in SPSS 22.0 software and GraphPad Prism 9 software. The data were expressed as mean ± standard deviation and compared by t test, Wilcoxon test, or Chi square test. DFS and OS were measured by Kaplan–Meier method, and the differences between groups were evaluated by log rank test. The independent predictive factors were determined by the cox proportional hazard model. All the statistical analyses, p < 0.05 were considered statistically significant.