Fig. 1

The expression and prognostic value of CLK1 in Human pancreatic cancer. a Flowchart showing the screening process of candidate genes by RNA-seq of normal tissues and PC tissues and alternative splicing analyses. b, c The TPM (transcripts per million (b); and FPKM (fragments per kilobase million (c)) of CLK1 in pancreatic tumor and adjacent normal tissues from GEO database were analyzed. n = 15 for normal tissues, n = 26 for tumor tissues. d The mRNA levels of CLK1 in 102 pairs of PDAC tumor and adjacent normal tissues were measured by qPCR. e, f Representative images of CLK1 protein levels in PDAC tumor and adjacent normal tissues by western blot assays (e). The changes of CLK1 protein expression in 103 pairs normal and tumor tissues were summarized (f). g The protein levels of CLK1 in normal human pancreatic duct epithelial (HPDE) cells and selected human pancreatic cancer cell lines were quantitated by western blot assays. Representative images are shown, and relative expression levels were summarized. h, i The expression of CLK1 in 186 paraffin-embedded specimens from the internal cohort was determined by TMA-based IHC staining. Representative IHC images are shown (h), and the relative CLK1 staining intensity was scored (i). Scale bar, 200 μm. j The number of PDAC tissues with high or low expression levels of CLK1 from patients with Stage III and Stage II pancreatic cancer was summarized. k–m Kaplan–Meier analyses of the correlations between CLK1 expression and overall survival of all PDAC patients (k), or Stage II patients (l), or Stage III patients (m) in the internal cohort. Data are shown as mean ± SD from three independent experiments. *P < 0.05; **P < 0.01; ***P < 0.001, between the indicated groups