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Background: Immunotherapy has demonstrated limited activity in prostate cancer to date. This likely reflects an immune suppressive tumor microenvironment (TME), with previous studies suggesting low PD-L1 expression and a sparse immune cell infiltrate. We aimed to further characterise the immune TME in primary prostate cancer and correlate immune subset densities with clinical outcomes. Methods: Two distinct cohorts of patients treated with radical prostatectomy were identified, based on the development of biochemical recurrence (BCR), one subgroup with high International Society of Urological Pathologists (ISUP) grade group, recurrent disease and a second with low grade, non-recurrent disease. A prostate immunohistochemical (IHC) antibody cocktail was used to differentiate tumor and peritumoral benign tissue. Specific CD8+, CD4+, FoxP3+, CD20+ and CD68+ cell subsets were identified using IHC staining of consecutive slides. PD-L1 and CD8/PD-L1 dual staining were also performed. Cell subset densities were quantified within tumor and peritumoral regions. We used descriptive statistics to report cell subset densities and T-tests to compare groups by age, grade and the development of BCR. Univariable and multivariable logistic regression were used to analyse risk factors for BCR and the development of metastatic disease. Results: A total of 175 patients were included, with a median age of 63 years and median pre-operative PSA of 8.2ng/ml. BCR occurred in 115 patients (66%) and 56 (32%) developed metastatic disease. CD68+ cells were the most abundant (median 648.8/mm2 intratumoral, 247.6/mm2 peritumoral), while PD-L1+ and PD-L1/CD8+ cell density was low overall (PD-L1+ median 162.4/mm2 intratumoral, 141.7/mm2 peritumoral; PD-L1/CD8+ (median 5.52/mm2 intratumoral, 3.41/mm2 peritumoral). Overall, grade group and T-stage were independently associated with BCR and metastatic disease. Higher density of peritumoral PD-L1+ cells was an independent risk factor for BCR (OR 5.33, 95%CI 1.31–21.61, p = 0.019).Although higher densities of CD8+ and CD4+ cells were observed in higher grade group 3–5 tumors, these were not associated with the development of BCR or metastasis. Conclusions: In our cohort of prostate cancer patients who underwent radical prostatectomy, higher grade group and T-stage were independent predictors of BCR and metastasis. Despite higher grade group being associated with higher CD8+ cell density, PD-L1+ and PD-L1/CD8+ cell densities were low overall, suggesting lower T cell receptor recognition of tumor antigens. Further understanding of this phenomenon would influence development of future immunotherapeutic strategies in prostate cancer. [ABSTRACT FROM AUTHOR]

Aim: To identify biochemical and genetic variation relating to increased risk of developing type 2 diabetes mellitus and cardiovascular disease in young, lean male and female adults of different ethnicities. Method: Fasting blood and urine and non-fasting blood following oral glucose intake were analysed in 90 Caucasians, South Asians and South East/East Asians. Results: There were no differences in age, birthweight, blood pressure, body mass index, percent body fat, total energy, percentage of macronutrient intake, microalbumin, leptin, cortisol, adrenocorticotropic hormone, nitric oxide metabolites, C-reactive protein, homocysteine, tumor necrosis factor-α, interleukin-6, von Willebrand factor, vascular cell adhesion molecule-1, plasminogen activator inhibitor-1, and tissue plasminogen activator. Fasting total cholesterol (P = .000), triglycerides (P = .050), low density lipoprotein (P = .009) and non-fasting blood glucose (15 min) (P = .024) were elevated in South Asians compared with Caucasians, but there was no significant difference in glucose area under curve (AUC). Non-fasting insulin in South Asians (15–120 min), in South East/East Asians (60–120 min), and insulin AUC in South Asians and South East/East Asians, were elevated compared with Caucasians (P≤0.006). The molar ratio of C-peptide AUC/Insulin AUC (P = .045) and adiponectin (P = .037) were lower in South Asians compared with Caucasians. A significant difference in allele frequency distributions in Caucasians and South Asians was found for rs2166706 (P = 0.022) and rs10830963 (P = 0.009), which are both near the melatonin receptor MTNR1B. Conclusions: Elevated non-fasting insulin exists in young South Asians of normal fasting glucose and insulin. Hepatic clearance of insulin may be reduced in South Asians. No current biochemical evidence exists of endothelial dysfunction at this stage of development. MTNR1B signalling may be a useful therapeutic target in Asian populations in the prevention of type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]