Fig. 1

The FLJ exhibits elevated expression levels in CRPC and is associated with a poor prognosis in prostate cancer. A The microarray volcano plot indicates the most significantly upregulated lncRNAs in 22Rv1. LncRNA-FLJ20021 (FLJ) is markedly upregulated in 22Rv1 (right panel). The red dots denote significantly upregulated lncRNAs in 22Rv1, whereas the blue dots represent significantly downregulated lncRNAs in LNCaP. Threshold: |logFC|> 2, in comparison to LNCaP, P < 0.05. B The TCGA database reveals the expression levels of FLJ in 51 normal prostate tissue samples and 489 PCa tissue samples. C Sangerbox biomedical data analysis reveals FLJ expression across various cancers, encompassing 52 normal prostate tissue samples and 495 PCa tissue samples. D qRT-PCR compared FLJ expression in normal prostate epithelial cells (RWPE-1), benign prostatic hyperplasia cells (BPH-1), androgen-dependent (LNCaP) and androgen-independent (22Rv1, C4-2, C4-2B) PCa cell lines, as well as AR-negative (PC3, DU145) PCa cell lines. E Representative RNA-FISH images of FLJ in 22 BPH and 50 PCa paraffin-embedded tissue samples, with a scale bar of 250 μm. F The mean fluorescence intensity of the representative RNA-FISH images was quantified using ImageJ. G RNA-FISH results in 22 BPH and 50 PCa paraffin-embedded tissue samples were quantified using ImageJ. H RNA-FISH results in 19 PCa paraffin-embedded tissue samples with pathological stages T1a-T2c and 31 samples with stages T3a-T4 were quantified using ImageJ. I RNA-FISH results in 15 PCa paraffin-embedded tissue samples with Gleason scores of 6–7 and 35 samples with scores of 8–10 were quantified using ImageJ. J Fluorescence images were scored based on mean fluorescence intensity (0–4 points) using ImageJ, and the proportion of scores was analyzed according to pathological stage (left) and Gleason score (right). K FLJ expression in 6 PCa tissues and their matched adjacent non-cancerous tissues was analyzed using qRT-PCR