Aims The four‐tiered peritoneal regression grading score (PRGS) assesses the response to chemotherapy in peritoneal metastasis (PM). The PRGS is used, for example, to assess the response to pressurised intraperitoneal aerosol chemotherapy (PIPAC). However, the reproducibility of the PRGS is currently unknown. We aimed to evaluate the inter‐ and intraobserver variability of the PRGS. Methods and results Thirty‐three patients who underwent at least three PIPAC treatments as part of the PIPAC‐OPC1 or PIPAC‐OPC2 clinical trials at Odense University Hospital, Denmark, were included. Prior to each therapy cycle, peritoneal quadrant biopsies were obtained and three haematoxylin and eosin (H&E)‐stained step sections were scanned and uploaded to a pseudonymised web library. For determining interobserver variability, eight pathologists assessed the PRGS for each quadrant biopsy, and Krippendorff's alpha and intraclass correlation coefficients (ICCs) were calculated. For determining intraobserver variability, three pathologists repeated their own assessments and Cohen's kappa and ICCs were calculated. A total of 331 peritoneal biopsies were analysed. Interobserver variability for PRGS of each biopsy and for the mean and maximum PRGS per biopsy set was moderate to good/substantial. The intraobserver variability for PRGS of each biopsy and for the mean and maximum PRGS per biopsy set was good to excellent/almost perfect. Conclusions Our data support the PRGS as a reproducible and useful tool to assess response to intraperitoneal chemotherapy in PM. Future studies should evaluate the prognostic and predictive role of the PRGS.

The results of the present study are in accordance with previous studies, and shows that the proposed methodology for standardized evaluation of TILs renders an acceptable inter-observer agreement. The findings, however, indicate that assessment of TILs needs further refinement, and is in support of the latest St. Gallen Consensus, that routine reporting of TILs for early breast cancer is not ready for implementation in a clinical setting.

Metastasis is the main cause of cancer-related deaths and remains the most significant challenge to management of the disease. Metastases are established through a complex multistep process involving intracellular signaling pathways. To gain insight to proteins central to specific steps in metastasis formation, we used a metastasis cell line model that allows investigation of extravasation and colonization of circulating cancer cells to lungs in mice. Using stable isotopic labeling by amino acids in cell culture and subcellular fractionation, the nuclear, cytosol, and mitochondria proteomes were analyzed by LC-MS/ MS, identifying a number of proteins that exhibited altered expression in isogenic metastatic versus nonmetastatic cancer cell lines, including NADH-cytochrome b5 reductase 3 (CYB5R3), L-lactate dehydrogenase A (LDHA), Niemann-pick c1 protein (NPC1), and nucleolar RNA helicase 2 (NRH2). The altered expression levels were validated at the protein and transcriptional levels, and analysis of breast cancer biopsies from two cohorts of patients demonstrated a significant correlation between high CYB5R3 expression and poor disease-free and overall survival in patients with estrogen receptor-negative tumors (DFS: p ‫؍‬ .02, OS: p ‫؍‬ .04). CYB5R3 gene knockdown using siRNA in metastasizing cells led to significantly decreased tumor burden in lungs when injected intravenously in immunodeficient mice. The cellular effects of CYB5R3 knock-down showed signaling alterations associated with extravasation, TGF␤ and HIF␣ pathways, and apoptosis. The decreased apoptosis of CYB5R3 knock-down metastatic cancer cell lines was confirmed in functional assays. Our study reveals a central role of CYB5R3 in extravasation/colonization of cancer cells and demonstrates the ability of our quantitative, comparative proteomic approach to identify key proteins of specific important biological processes that may also prove useful as potential biomarkers of clinical relevance.

Although the study in general showed a moderate to good inter-observer agreement according to both ICC and Lights Kappa, still major discrepancies were identified in especially the mid-range of observations. Consequently, for now Ki67 estimation is not implemented in the DBCG treatment algorithm.

Background and Aims: Reliable noninvasive biomarkers are an unmet clinical need for the diagnosis of NASH. This study investigates the diagnostic accuracy of the circulating triggering receptor expressed on myeloid cells 2 (plasma TREM2) as a biomarker for NASH in patients with NAFLD and elevated liver stiffness. Approach and Results: We collected cross‐sectional, clinical data including liver biopsies from a derivation (n = 48) and a validation cohort (n = 170) of patients with elevated liver stiffness measurement (LSM ≥ 8.0 kPa). Patients with NAFLD activity scores (NAS) ≥4 were defined as having NASH. Plasma TREM2 levels were significantly elevated in patients with NASH of the derivation cohort, with an area under the receiver operating characteristics curve (AUROC) of 0.92 (95% confidence interval [CI], 0.84–0.99). In the validation cohort, plasma TREM2 level increased approximately two‐fold in patients with NASH, and a strong diagnostic accuracy was confirmed (AUROC, 0.83; 95% CI, 0.77–0.89; p < 0.0001). Plasma TREM2 levels were associated with the individual histologic features of NAS: steatosis, lobular inflammation, and ballooning (p < 0.0001), but only weakly with fibrosis stages. Dual cutoffs for rule‐in and rule‐out were explored: a plasma TREM2 level of ≤38 ng/ml was found to be an optimal NASH rule‐out cutoff (sensitivity 90%; specificity 52%), whereas a plasma TREM2 level of ≥65 ng/ml was an optimal NASH rule‐in cutoff (specificity 89%; sensitivity 54%). Conclusions: Plasma TREM2 is a plausible individual biomarker that can rule‐in or rule‐out the presence of NASH with high accuracy and thus has the potential to reduce the need for liver biopsies and to identify patients who are eligible for clinical trials in NASH.