Fig 2: Factorial Discriminant Analysis (FAD) carried out to describe the variables that discriminate the three groups of patients. RAR beta 2, ER alpha, RGMA and PGR variables conflict to EZH2. Variable SRC3 being away from the circle, it wears a low information (left panel). The graphical representation of patients was used to identify homogeneous groups within the population from the point of view of variable studied (H3K27me3). Red plots represent normal patients (N), green plots represent patients with Gleason score = 7 (<=7) and blue plots represent patients with Gleason score >7 (>7) (right panel).

Fig 3: Principal component analysis (PCA) carried out to explore the relationships between H3K27 levels and clinicopathological parameters. H3K27me3 level was evaluated by PCA analysis. H3K27me3 levels on ER alpha, RAR beta 2, RGMA and PGR genes correlated positively with PSA level (PSA), clinical stage (patho) and Gleason score (Gleason).

Fig 4: EZH2 , AR and SRC3 is upregulated in prostate cancer and inversely correlated with RAR beta 2 , ER alpha , PGR and RGMA . mRNA expression of seven genes were measured using RT-qPCR in normal tissues (n = 38) and cancerous tissues (n = 34). 18S RNA was used as an internal control in PCR reactions. All genes that have high H3K27me3 levels in their promoter are consistent with the low mRNA expression levels. In contrast, genes that have low H3K27me3 levels are consistent with high mRNA expression levels. Analysis of variance, followed by a Tukey multiple comparison test, was used for statistical analysis. The statistical significant between groups was indicated by letters “a”, “b” and “c”. (N = normal; GS = Gleason score).

Fig 5: Assessment of H3K27me3 marks in normal and tumoral tissues using ChIP-qPCR. ChIP analysis indicates the change of H3K27me3 marks at six gene loci in prostate cancer tissues. H3K27me3 level on EZH2 was found to be lower in prostate cancer tissues (n = 32) versus normal tissues (n = 33). Contrariwise, the H3K27me3 level of RAR beta 2, PGR, ER alpha and RGMA was significantly higher in tumoral tissues that in normal tissues. The H3K27me3 level on SRC3 in cancer tissue did not reach statistical significance compared in normal tissue. The data is expressed as % of input. Analysis of variance, followed by a Tukey multiple comparison test, was used for statistical analysis. The statistical significant between groups was indicated by letters “a”, “b” and “c”. (N = normal; GS = Gleason score).