CD40. We present more evidence of the case of CD40 as a biomarker, since a probe for CD40 (BX381481) ranks 6 th (the Spearman correlation of the probe expression with the Jensen-Shannon divergence from the equiprobability distribution is 20.5764). CD40 is a member of the TNF receptor superfamily. Notably, in 56 out of 57 archival prostate cancer samples Palmer et al. have reported no CD40 expression [518] . However, CD40 expression was present in normal prostatic acini, so they proposed that ''invasive prostate cancer is a CD40-negative tumour'' (see the previous results of Moghaddami et. al. [514] ). Matching our observations, they proposed that CD40 provides ''insight into progression of cancer from normal epithelium''; our proposed methodology is revealing this fact as well. Depletion of CD40 in the tumour microenvironment may be central in avoiding the action of the immune system [506] , as prostate cancer induces a progressive suppression of the dendritic cell system [520] . It is perhaps a central piece which should be put together in the context of other pieces of information coming from immunotherapy [508, 512, 513, 516] and pharmacological studies [507] that warrant serious investigation towards the design of new and improved clinical studies [508, 517] .