Fig. 1

SNORA37 is associated with unfavorable prognosis of gastric cancer. a Heatmap illustrating the differential expression (fold change ≥ 2.0, P-value < 0.05) of snoRNAs between three pairs of pathological validated gastric cancer and corresponding normal epithelial tissues. b Validating RT-PCR assay showing the expression levels of eight snoRNAs in gastric cancer (GC) and corresponding normal (CN) epithelial tissues. GAPDH served as a control. c The expression levels of SNORA37 in normal gastric epithelia and gastric cancer tissues derived from TCGA (https://cancergenome.nih.gov) and TNM-plot (https://tnmplot.com/) databases. d Real-time qRT-PCR assay showing the relative expression of snoRNAs (normalized to GAPDH, n = 4) in GES-1, MKN-45, HGC-27, AGS, and SNU-1 cells. e Kaplan–Meier curves indicating overall survival (OS) and first progression (FP) survival of gastric cancer cases with low or high levels of SNORA37 (cutoff values = 4.95 and 5.08, respectively). f Schematic representation showing genomic location of SNORA37 derived from its host gene MBD2, and validation by Sanger sequencing. g Real-time qRT-PCR indicating the distribution of SNORA37, GAPDH, and U1 in cytoplasmic and nuclear fractions of HGC-27 and AGS cells (n = 4). h RNA-FISH assay visualizing the cytoplasmic and nuclear localization of SNORA37 (red, arrowheads) in HGC-27 cells, with nuclei staining with DAPI (blue). SNORA37 sense probe was used as a negative control. GAPDH and U1 were used as positive controls. Non-parametric Mann–Whitney U test compared the difference in c. One-way analysis of variance (ANOVA) compared the difference in d. Log-rank test was used for survival comparison in e. *P < 0.05, ** P < 0.01, *** P < 0.001 vs. normal or GES-1. ns, non-significant. Data are shown as mean ± s.e.m. (error bars) and representative of three independent experiments in b, d, g and h