NOMINATOR: Feasibility of genomic testing of rare cancers to match cancer to treatment.

Background: Rare cancers (RCs) often lack proven treatments and consequently have poorer outcomes. Identification of molecular biomarkers can facilitate treatment selection and trials access for RC patients (pts) where histology-based trials are not feasible. We assessed the potential for next-generation sequencing (NGS) to impact RC care. Methods: Pts with a rare histology, poor-prognosis solid-tumor and no standard of care therapy underwent NGS genomic profiling of paired FFPE tumor and blood (PMCC comprehensive cancer panel; 391 genes). A virtual molecular tumour board (MTB) reviewed curated results regarding diagnosis, actionability (OncoKB) and treatment recommendations. Results: Between July 2017 and Nov 2019, 121 pt were prospectively enrolled across 4 Australian sites. 109 (91%) pts had a tumour with an incidence of 10%) were: TP53 (45%), CDKN2A/B, RB1, PTEN and NF1. 51 (51%) had at least one potentially actionable finding, with 27 matched to a clinically validated drug (OncoKB level 3 or better) [Table]. In 6 cases NGS resulted in a revised diagnosis (includes 4 with FDA approved therapy). Actionable germline mutations were detected in 3 individuals of which 2 were previously known. The majority of pts remain in follow-up, however, 8 died prior to or within 28 days of NGS result availability. Drug access remains a limitation with only 12 receiving therapy based on NGS/MTB guidance. Clinical trial information: ACTRN12616001000493. Conclusions: NGS in RCs is feasible with potential impact in half of cases. Earlier testing and improved off-label/trial drug access is necessary to increase the likelihood that RC patients may benefit from molecularly guided therapy

Adult cardiac-resident MSC-like stem cells with a proepicardial origin

Colony-forming units – fibroblast (CFU-Fs), analogous to those giving rise to bone marrow (BM) mesenchymal stem cells (MSCs), are present in many organs, although the relationship between BM and organ-specific CFU-Fs in homeostasis and tissue repair is unknown. Here we describe a population of adult cardiac-resident CFU-Fs (cCFU-Fs) that occupy a perivascular, adventitial niche and show broad trans-germ layer potency in vitro and in vivo. CRE lineage tracing and embryo analysis demonstrated a proepicardial origin for cCFU-Fs. Furthermore, in BM transplantation chimeras, we found no interchange between BM and cCFU-Fs after aging, myocardial infarction, or BM stem cell mobilization. BM and cardiac and aortic CFU-Fs had distinct CRE lineage signatures, indicating that they arise from different progenitor beds during development. These diverse origins for CFU-Fs suggest an underlying basis for differentiation biases seen in different CFU-F populations, and could also influence their capacity for participating in tissue repair