Mahal BA, Alshalalfa M, Zhao SG, et al. - Given that prostate cancer progression is known as a complex, multistep process that includes molecular changes in cells of the tumor and the microenvironment, with related interactions between the stroma and epithelium, and keeping this in mind, researchers undertook genomic expression analyses of stromal infiltration markers in order to know the importance thereof in prostate cancer. Using a prospective registry cohort (n = 5,239) and 3 retrospective institutional cohorts (n = 1,135), the evaluation of genome-wide expression profiles of formalin-fixed, paraffin-embedded radical prostatectomy samples was performed. Stromal infiltration was indicated by two independent stromal gene expression signatures. Findings revealed a correlation between the expression of stromal infiltration markers and prostate cancer aggressiveness/progression. Response to radiation therapy (RT) may be predicted by the expression of stromal infiltration markers; a metastasis-free survival benefit related to postoperative RT was noted for patients with high stromal scores, but not for those with low stromal scores. Experts recommended examining stromal infiltration markers and considering these for inclusion into clinical prognostication and decision making.