Prostate cancer (PCa) is the most prevalent cancer in men. Hyperactive STAT3 is thought to be oncogenic in PCa. However, targeting of the IL-6/STAT3 axis in PCa patients has failed to provide therapeutic benefit. Here we show that genetic inactivation of Stat3 or IL-6 signalling in a Pten-deficient PCa mouse model accelerates cancer progression leading to metastasis. Mechanistically, we identify p19ARF as a direct Stat3 target. Loss of Stat3 signalling disrupts the ARF–Mdm2–p53 tumour suppressor axis bypassing senescence. Strikingly, we also identify STAT3 and CDKN2A mutations in primary human PCa. STAT3 and CDKN2A deletions co-occurred with high frequency in PCa metastases. In accordance, loss of STAT3 and p14ARF expression in patient tumours correlates with increased risk of disease recurrence and metastatic PCa. Thus, STAT3 and ARF may be prognostic markers to stratify high from low risk PCa patients. Our findings challenge the current discussion on therapeutic benefit or risk of IL-6/STAT3 inhibition.

Tumor-infiltrating immune cells are highly relevant for prognosis and identification of immunotherapy targets in hepatocellular carcinoma (HCC). The recently developed CIBERSORT method allows immune cell profiling by deconvolution of gene expression microarray data. By applying CIBERSORT, we assessed the relative proportions of immune cells in 41 healthy human livers, 305 HCC samples and 82 HCC adjacent tissues. The obtained immune cell profiles provided enumeration and activation status of 22 immune cell subtypes. Mast cells were evaluated by immunohistochemistry in ten HCC patients. Activated mast cells, monocytes and plasma cells were decreased in HCC, while resting mast cells, total and naïve B cells, CD4+ memory resting and CD8+ T cells were increased when compared to healthy livers. Previously described S1, S2 and S3 molecular HCC subclasses demonstrated increased M1-polarized macrophages in the S3 subclass with good prognosis. Strong total immune cell infiltration into HCC correlated with total B cells, memory B cells, T follicular helper cells and M1 macrophages, whereas weak infiltration was linked to resting NK cells, neutrophils and resting mast cells. Immunohistochemical analysis of patient samples confirmed the reduced frequency of mast cells in human HCC tumor tissue as compared to tumor adjacent tissue. Our data demonstrate that deconvolution of gene expression data by CIBERSORT provides valuable information about immune cell composition of HCC patients.

Summary Background HIV/HCV co‐infected patients show accelerated fibrosis progression and higher risk for complications of portal hypertension (PHT). Aim To assess the effects of interferon‐free therapy on portal pressure, liver histology and plasma biomarkers in HIV/HCV‐coinfected patients with PHT. Methods Twenty‐two patients with paired hepatic venous pressure gradient (HVPG) measurements prior and after successful treatment (SVR) with interferon‐free regimens were included. Liver stiffness was assessed by transient elastography and biopsies were scored according to METAVIR. Plasma biomarkers were determined by ELISA. Results Overall, HVPG decreased from 10.7 ± 4.1 mmHg at baseline to 7.4 ± 4.2 mmHg after HCV treatment (Δ:‐3.3 ± 2.7 mmHg; p < 0.001). In patients with clinically significant PHT (HVPG≥10 mmHg, n = 11), HVPG decreased from 14.1 ± 2.9 to 10.4 ± 3.9 mmHg (Δ:‐3.7 ± 3.3 mmHg; p = 0.004) and a haemodynamic response (HVPG decrease ≥10%) was observed in 73%. In 64% of patients with subclinical PHT (HVPG 6–9 mmHg, n = 11), portal pressure normalised at SVR. Mean liver stiffness decreased from 20.8 kPa to 11.5 kPa (Δ:‐8.8 ± 7.4 kPa; p < 0.001). Fifty percent (7/14) of patients with cirrhosis were re‐classified as METAVIR ≤F3 and all patients with decompensated cirrhosis improved their Child–Pugh stage. After successful HCV treatment, 39% still had persistent histological necroinflammatory activity (METAVIR A1), which correlated with less HVPG response and more steatosis. While most biomarkers improved with SVR, METAVIR A1 patients had significantly higher plasma levels of fibrogenic (PDGF, TGF‐β) and angiogenic (VEGF, Angiopoietin1) biomarkers. Conclusions Interferon‐free therapy reduces PHT and halts histological necroinflammatory activity in the majority of HIV/HCV‐coinfected patients after SVR, which may lead to re‐compensation of liver function in cirrhosis. Biomarkers could identify patients with persisting hepatic necroinflammation.

Medullary carcinoma (MTC) is an aggressive tumour that derives from the thyroid parafollicular calcitonin-secreting cells (C cells). Lymph node metastasis may occur early in disease pathogenesis and is one of the most important negative prognostic parameters. Surgery is the only curative therapy while chemotherapeutic options are limited. Neuroendocrine differentiated C cells may express somatostatin receptors (SSTR), which have a wide range of biological actions including inhibitory effects on cell survival and angiogenesis and antiproliferative effects on cancer cell lines. Moreover, they are a potential target for various somatostatin analogues. Aim of this study was to analyse the protein expression of SSTR2A and 5 in MTCs with or without the presence of lymph node metastases in correlation with various clinicopathological parameters. This retrospective immunohistochemical analysis included 97 patients with medullary thyroid carcinomas. Protein expression was detected by immunohistochemistry for somatostatin receptors 2A and 5. Various clinicopathological parameters, such as Ki-67 proliferation index or presence of desmoplasia, were included for statistical analysis. SSTR2A protein expression significantly correlated with the presence of lymph node metastases (p = 0.009), locally advanced MTCs staged according to the TNM (p < 0.001) and degree of desmoplasia (p = 0.029). Although SSTR5 protein expression significantly correlated with advanced stages of MTCs (p = 0.023) and degree of desmoplasia (p = 0.020), no correlation was found with the presence of lymph node metastases. Our results provide additional information concerning the aggressiveness of MTCs and reveal that a high SSTR2A and SSTR5 expression might be a poor prognostic feature.

Background and Aims Increased fatty acid (FA) flux from adipose tissue to the liver contributes to the development of NAFLD. Because free FAs are key lipotoxic triggers accelerating disease progression, inhibiting adipose triglyceride lipase (ATGL)/patatin‐like phospholipase domain containing 2 (PNPLA2), the main enzyme driving lipolysis, may attenuate steatohepatitis. Approach and Results Hepatocyte‐specific ATGL knockout (ATGL LKO) mice were challenged with methionine‐choline–deficient (MCD) or high‐fat high‐carbohydrate (HFHC) diet. Serum biochemistry, hepatic lipid content and liver histology were assessed. Mechanistically, hepatic gene and protein expression of lipid metabolism, inflammation, fibrosis, apoptosis, and endoplasmic reticulum (ER) stress markers were investigated. DNA binding activity for peroxisome proliferator‐activated receptor (PPAR) α and PPARδ was measured. After short hairpin RNA–mediated ATGL knockdown, HepG2 cells were treated with lipopolysaccharide (LPS) or oleic acid:palmitic acid 2:1 (OP21) to explore the direct role of ATGL in inflammation in vitro. On MCD and HFHC challenge, ATGL LKO mice showed reduced PPARα and increased PPARδ DNA binding activity when compared with challenged wild‐type (WT) mice. Despite histologically and biochemically pronounced hepatic steatosis, dietary‐challenged ATGL LKO mice showed lower hepatic inflammation, reflected by the reduced number of Galectin3/MAC‐2 and myeloperoxidase‐positive cells and low mRNA expression levels of inflammatory markers (such as IL‐1β and F4/80) when compared with WT mice. In line with this, protein levels of the ER stress markers protein kinase R–like endoplasmic reticulum kinase and inositol‐requiring enzyme 1α were reduced in ATGL LKO mice fed with MCD diet. Accordingly, pretreatment of LPS‐treated HepG2 cells with the PPARδ agonist GW0742 suppressed mRNA expression of inflammatory markers. Additionally, ATGL knockdown in HepG2 cells attenuated LPS/OP21‐induced expression of proinflammatory cytokines and chemokines such as chemokine (C‐X‐C motif) ligand 5, chemokine (C‐C motif) ligand (Ccl) 2, and Ccl5. Conclusions Low hepatic lipolysis and increased PPARδ activity in ATGL/PNPLA2 deficiency may counteract hepatic inflammation and ER stress despite increased steatosis. Therefore, lowering hepatocyte lipolysis through ATGL inhibition represents a promising therapeutic strategy for the treatment of steatohepatitis.