Fig. 5: Higher expression of BCAS2 was detected in more aggressive human prostate cancer (PCa) and was associated with the expression of β-catenin.

a Representative images of IHC staining for BCAS2 and β-catenin in PCa tissues. Lower expression levels in both BCAS2 and β-catenin were found in the same PCa tissue with a Gleason grade equal to 2 (left panels). Note that the upper and lower panels are from sections that are close to each other. Intermediate expression levels of both BCAS2 and β-catenin were observed in the same PCa tissue with a Gleason grade equal to 3 (middle panels). Higher expression levels in both BCAS2 and β-catenin were detected in the same PCa, where the highest Gleason grade equal to 5 (right panels). Brown, positive IHC signals by diaminobenzidine; light blue, haematoxylin counterstain (with decreased staining time to avoid the masking effect of haematoxylin on the IHC signals in the nucleus). Scale bar = 100 μm. b The BCAS2 IHC scores significantly differed between benign lesions and Gleason grade 5 tumours, between Gleason grade 1 and grade 5 tumours, and between Gleason grade 1 and grade 2.5–3 tumours (*P < 0.05; Mann–Whitney U test). c The BCAS2 IHC score of pathology grade 3.5–4 tumours was significantly higher than those of grades 1–1.5, 2, 1–2 or 2–2.5 (*P < 0.05; Mann–Whitney U test). d The BCAS2 expression level (represented as the IHC score) correlated with β-catenin expression level. The BCAS2 IHC scores exhibited a significant positive correlation with the β-catenin score (Spearman r = 0.4979, P < 0.0001). PCa (n = 118) and benign hyperplasia (n = 18) tissue sections were subjected to IHC using anti-BCAS2 or anti-β catenin antibody. We scored the IHC results by multiplying the intensity score of staining (0 ~ +3) and the percentage of the positively stained area. e The survival analysis showed that high levels of BCAS2 mRNA in PCa tissues were significantly correlated with shorter survival in patients with PCa. The high expression level was defined as BCAS2 mRNA of more than 30.42 fragments per kilobase of exon per million reads (FPKM). The low expression level was defined as equal to or <30.42 FPKM. The survival analysis was performed by the Kaplan–Meier method using GraphPad software and data from The Human Protein Atlas⁴⁴ website (https://www.proteinatlas.org; https://www.proteinatlas.org/ENSG00000116752-BCAS2/pathology/prostate+cancer). RNA sequencing data were reported as the median FPKM and generated by The Cancer Genome Atlas (https://www.genome.gov/Funded-Programs-Projects/Cancer-Genome-Atlas). The log-rank (Mantel–Cox) test was used to evaluate the significance of the difference. Note that PCa patients with a high level of BCAS2 mRNA (n = 213) had significantly shorter (P < 0.05) survival than those with a low level of BCAS2 mRNA (n = 281).