Figure 3.

Associations between expression of various HERV transcripts in prostate cancer tissue. (A) Heat map showing the differential expression (log₂ fold difference; FD) of HERV RNA transcripts in prostate cancer tissues from men with prostate cancer. Left panels show expression of HERV-K Np9, HERV-W Gag, HERV-E Pol and HERV-H Pol in malignant regions relative to benign regions of the prostate (each standardised to GAPDH). Right panels show expression of HERV-K Gag and HERV-E Env in both benign (B) and malignant (M) regions relative to expression of GAPDH (due to transcripts being undetectable in many benign tissue samples). (B) Correlation matrix showing the association between expression levels of the various HERV transcripts as determined by non-parametric Spearman’s correlation. For HERV-K Gag and HERV-E Env, the expression level in malignant tissues (relative to GAPDH) was analysed, whilst for all other transcripts, the expression in malignant tissue relative to benign tissue (both standardised to GAPDH) was used. Values show Spearman’s rho. * and ** indicate p < 0.05 and 0.01, respectively.