Highlights d Cancer-associated fibroblasts contribute to pancreatic cancer heterogeneity d Cancer cells can have a double-positive phenotype: proliferation and invasion d High CAF abundance linked with DP cells enriched for MAPK and STAT3 co-signaling d Intra-tumoral gland types provide tissue heterogeneity linked with clinical outcome

Statement of Translational RelevanceDetection of persistent circulating tumor DNA (ctDNA) after curative-intent surgery to identify patients with minimal residual disease (MRD) who will ultimately recur has emerged as a potentially transformative approach in oncology. Early identification of patients with MRD through ctDNA detection could identify patients in whom additional therapy might salvage the chance of cure. To date, ctDNA MRD assays have employed a tumor-informed approach, requiring initial sequencing of tumor tissue to guide ctDNA detection, and thus cannot be used when a patient has insufficient tumor tissue for analysis. Here, we evaluate the first tumoruninformed, plasma-only ctDNA assay integrating genomic and epigenomic signatures to detect MRD in post-operative colorectal cancer (CRC) patients, without requiring parallel tumor sequencing, which produced favorable sensitivity and specificity, comparable to tumor-informed approaches. These data highlight the feasibility and potential clinical utility of plasma-only ctDNA-guided MRD detection.

Cancer growth and metastasis are regulated in part by stromal cells such as fibroblasts and immune cells within the tumor microenvironment. Endothelial cells (ECs) are also ubiquitous within tumors because tumors are vascular, and yet, the impact of tumor-resident ECs is less well understood. Through paracrine regulation, ECs modulate a diverse spectrum of pathophysiologic processes in normal and hyperplastic tissues. We hypothesized that ECs offer similar paracrine regulatory control of cancer biology. Indeed, secretions from quiescent ECs muted the proliferative and invasive phenotype of lung and breast cancer cells in vitro and reduced cancer cell protumorigenic and pro-inflammatory signaling. EC perlecan silencing significantly changed this regulatory relationship, eliminating the ability of ECs to inhibit cancer cell invasiveness via increased interleukin-6 secretion. Moreover, implanting ECs embedded within porous matrices slowed adjacent xenograft tumor growth and prevented architectural degeneration, with a concomitant reduction in proliferative and tumorigenic markers. Finally, lung carcinoma cells pretreated with intact EC-conditioned media, but not media conditioned with perlecan-silenced ECs, exhibited reduced micrometastatic burden after tail vein injection. These findings add to an emerging appreciation of EC-regulatory effects that transcend their structural roles and pave the way for improved characterization and control of EC-cancer cross-talk interactions for diagnosis, prognosis, and treatment of cancer.