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Genomic profiling of pancreatic cancer using small core biopsies has taken an increasingly prominent role in precision medicine. However, if not appropriately preserved, nucleic acids (NA) from pancreatic tissues are known to be susceptible to degradation due to high intrinsic levels of nucleases. PAXgene fixation (PreAnalytix, Switzerland) represents a novel formalin-free tissue preservation method. We sought to compare the NA and histomorphological preservation of pancreatic cancer tissues preserved with PAXgene-fixed paraffin-embedding (PFPE) and formalin-fixed paraffin-embedding (FFPE). Tissues from 19 patients were obtained prospectively from pancreaticoduodenectomy specimens and evaluated by four gastrointestinal pathologists. The extracted NA were quantified by Nanodrop and Qubit and assessed for quality by qPCR, targeted next-generation sequencing (NGS) assay, and RNA-sequencing. Our results demonstrated that, when assessed blindly for morphological quality, the four pathologists deemed the PFPE slides adequate for diagnostic purposes. PFPE tissues enable greater yields of less fragmented and more amplifiable DNA. PFPE tissues demonstrated significantly improved quality control (QC) metrics in a targeted NGS assay including Median Absolute Pair-wise Difference (MAPD) scores. Our results support the use of PAXgene fixative for the processing of specimens from pancreatic cancers with the potential benefits of improved yields for more amplifiable DNA in low-yield biopsy specimens and its ideal use for amplicon-based NGS assays.

Highlights • NK cell infiltration to solid tumors independently predicts improved OS. • We reviewed 53 studies and meta-analyzed hazard ratios from 30. • Meta-analysis revealed that NK cell infiltration predicts decreased risk of death. • NK prognostic value is related to identifying marker and subtumor location. • NK cell infiltration may be associated with tumor stage and grade., The immune landscape of a tumor is highly connected to patient prognosis and response to treatment, but little is known about how natural killer (NK) cells predict overall survival (OS) among patients with solid tumors. We present the first meta-analysis on NK cell infiltration into solid tumors as a prognostic indicator for OS, considering cancer types independently, and together. Samples were collected from 1973 to 2016 with results published between 1989 and 2020. From 53 studies, we found that NK cell infiltration corresponds with decreased risk of death (HR=0.34, 95% CI: 0.26–0.46; p

NK cell education is determined by inhibitory KIR and HLA, but how their interactions potentiate reactivity is unknown. Human NK cells derived from CD34+ stem cells transplanted into a novel HLA-B*27:05 transgenic mouse are educated by HLA on both donor human hematopoietic cells and recipient mouse stromal cells. Similarly, NK reactivity in hematopoietic cell transplant patients reflects education by both donor and recipient HLA. Upon transfer to HLA-B*27:05+ mice, mature, uneducated KIR3DL1+ NK cells gain reactive potential, demonstrating that NK cell education can respond to alterations in the HLA available in the local environment. Bone marrow chimera studies reveal that HLA from either hematopoietic or stromal cells is sufficient for this re-education. Strikingly, educated NK cells do not lose reactivity after transfer to HLA-negative mice, implicating a cell-intrinsic contribution of HLA to the maintenance of NK education. We find that HLA knockdown diminishes NK reactivity, and FRET studies reveal that HLA and KIR complex in cis. HLA can be acquired from neighboring cells by trogocytosis, illuminating a mechanism by which ligands can be acquired from trans sources for cis education of NK cells. Altogether, these findings define how KIR and HLA shape NK function and may be applicable in cell therapies to potentiate donor NK reactivity.