Dense tumor-infiltrating lymphocytes (TILs) in liver metastasis from colorectal cancer are related to improved overall survival.

BACKGROUND AND OBJECTIVES: Tumor-infiltrating lymphocytes (TILs) represent a host-tumor interaction, frequently signifying an augmented immunological response. Nonetheless, implications with survival outcomes in patients with colorectal carcinoma liver metastasis (CRLM) warrant rigorous validation. The objective was to demonstrate the association between TILs and survival in patients with CRLM. METHOD: In a retrospective evaluation conducted in a single institution, we assessed all patients who underwent hepatectomy due to CRLM between 2014 and 2018. Comprehensive medical documentation reviews were executed. TILs were assessed by a liver pathologist, blinded to the clinical information, in all surgical slides. RESULTS: This retrospective cohort included 112 patients. Median overall survival (OS) was 58 months and disease-free survival (DFS) was 12 months for the entire cohort. Comparison between groups showed a median OS of 81 months in the dense TILs group and 40 months in the weak/absent group (p = 0.001), and DFS was 14 months versus 9 months (p = 0.041). Multivariable analysis showed that TILs were an independent predictor of OS (HR 1.95; p = 0.031). CONCLUSIONS: Dense TILs are a pivotal prognostic indicator, correlating with enhanced OS. Including TILs information in histopathological evaluations should refine the clinical decision-making process for this group of patients.

Mature tertiary lymphoid structures are key niches of tumour-specific immune responses in pancreatic ductal adenocarcinomas.

OBJECTIVE: To better understand the immune microenvironment of pancreatic ductal adenocarcinomas (PDACs), here we explored the relevance of T and B cell compartmentalisation into tertiary lymphoid structures (TLSs) for the generation of local antitumour immunity. DESIGN: We characterised the functional states and spatial organisation of PDAC-infiltrating T and B cells using single-cell RNA sequencing (scRNA-seq), flow cytometry, multicolour immunofluorescence, gene expression profiling of microdissected TLSs, as well as in vitro assays. In addition, we performed a pan-cancer analysis of tumour-infiltrating T cells using scRNA-seq and sc T cell receptor sequencing datasets from eight cancer types. To evaluate the clinical relevance of our findings, we used PDAC bulk RNA-seq data from The Cancer Genome Atlas and the PRINCE chemoimmunotherapy trial. RESULTS: We found that a subset of PDACs harbours fully developed TLSs where B cells proliferate and differentiate into plasma cells. These mature TLSs also support T cell activity and are enriched with tumour-reactive T cells. Importantly, we showed that chronically activated, tumour-reactive T cells exposed to fibroblast-derived TGF-ß may act as TLS organisers by producing the B cell chemoattractant CXCL13. Identification of highly similar subsets of clonally expanded CXCL13 + tumour-infiltrating T cells across multiple cancer types further indicated a conserved link between tumour-antigen recognition and the allocation of B cells within sheltered hubs in the tumour microenvironment. Finally, we showed that the expression of a gene signature reflecting mature TLSs was enriched in pretreatment biopsies from PDAC patients with longer survival after receiving different chemoimmunotherapy regimens. CONCLUSION: We provided a framework for understanding the biological role of PDAC-associated TLSs and revealed their potential to guide the selection of patients for future immunotherapy trials.

Assessment of the aerosol distribution pattern of a single-port device for intraperitoneal administration of therapeutic substances.

BACKGROUND: In the last 20 years, intraperitoneal chemotherapy (IPC) has been explored as a modality for the management of peritoneal metastases of gynecologic, gastrointestinal, and primary peritoneal tumors. Direct delivery of chemotherapeutic agents to the peritoneal cavity space has proved superior to systemic chemotherapy when evaluating characteristics such as drug concentration reached in the peritoneal space, penetration into peritoneal metastases, and chemotherapy-related toxicity. Traditionally, IPC is delivered by peritoneal lavage with a liquid solution. This form of delivery has limitations, including inhomogeneous intraperitoneal distribution and limited ability to penetrate tissues and metastatic nodules. An alternative mode of delivery is so-called pressurized intraperitoneal aerosol chemotherapy (PIPAC). Within this context, the present study sought to identify the pattern of spatial distribution of therapeutic solutions aerosolized into the peritoneal space using a single-port PIPAC device and ascertain whether the aerosolized method is superior to the traditional (liquid) mode of IPC delivery. METHODS: Analysis of the rate of intra-abdominal staining with aerosolized 2% silver nitrate in five porcine models. RESULTS: Assessment of differences in stain impregnation between the upper, middle, and lower abdomen did not reveal significant differences (p = 0.42). The median sum scores were 1 for the upper abdomen and 3 for the middle and lower abdomen. CONCLUSIONS: Aerosolization does not reach all regions of the abdomen homogeneously. However, adequate exposure of the upper abdomen, mid-abdomen, and lower abdomen to chemotherapeutic agents can be achieved with PIPAC.

Exome and Tissue-Associated Microbiota as Predictive Markers of Response to Neoadjuvant Treatment in Locally Advanced Rectal Cancer.

The clinical and pathological responses to multimodal neoadjuvant therapy in locally advanced rectal cancers (LARCs) remain unpredictable, and robust biomarkers are still lacking. Recent studies have shown that tumors present somatic molecular alterations related to better treatment response, and it is also clear that tumor-associated bacteria are modulators of chemotherapy and immunotherapy efficacy, therefore having implications for long-term survivorship and a good potential as the biomarkers of outcome. Here, we performed whole exome sequencing and 16S ribosomal RNA (rRNA) amplicon sequencing from 44 pre-treatment LARC biopsies from Argentinian and Brazilian patients, treated with neoadjuvant chemoradiotherapy or total neoadjuvant treatment, searching for predictive biomarkers of response (responders, n = 17; non-responders, n = 27). In general, the somatic landscape of LARC was not capable to predict a response; however, a significant enrichment in mutational signature SBS5 was observed in non-responders (p = 0.0021), as well as the co-occurrence of APC and FAT4 mutations (p < 0.05). Microbiota studies revealed a similar alpha and beta diversity of bacteria between response groups. Yet, the linear discriminant analysis (LDA) of effect size indicated an enrichment of Hungatella, Flavonifractor, and Methanosphaera (LDA score ≥3) in the pre-treatment biopsies of responders, while non-responders had a higher abundance of Enhydrobacter, Paraprevotella (LDA score ≥3) and Finegoldia (LDA score ≥4). Altogether, the evaluation of these biomarkers in pre-treatment biopsies could eventually predict a neoadjuvant treatment response, while in post-treatment samples, it could help in guiding non-operative treatment strategies.