Abstract 2027: Serological assessment of cancer associated myo-fibroblast (myCAF) activity by collagen pro-peptide biomarkers provides high prognostic power

Abstract Background: Myofibroblast Cancer Associated Fibroblasts (myCAFs) are the main tumor fibrosis drivers and hence different from inflammatory CAFs (iCAFs). MyCAFs are emerging as an important tool for understanding tumor biology. CAFs produce type III, V, VI and XI collagen that are the essential components of tumor fibrosis. Pro-peptides of these collagens can be quantified both in serum with the PRO-C3, PRO-C5, PRO-C6 and PRO-C11 biomarkers where they are prognostic for poor overall survival in patients with various solid tumor types and may be applied in vitro. Here we investigated the association and difference between myCAFs and iCAFs and their collagen expression profile and related that to data available data on serological assessments of PRO-C3, PRO-C5, PRO-C6 and PRO-C11, and cultured CAFs. Methods: The collagen expression in CAF subtypes were established from publicly available single-cell RNA-Seq dataset from pancreas cancer (PMID: 31273297) and non-small cell lung cancer (PMID: 36973297). In addition, we generated a biomarker profile using PRO-C3, PRO-C5, PRO-C6 and PRO-C11 ELISA to measure in serum of 220 patients with various solid tumor types and 33 healthy controls. We cultured CAFs in vitro and measured the same biomarkers in conditioned medium. We compared the result to historical PRO-C3, PRO-C6 and PRO-C11 prognostic data for pancreas cancer patient data. Results: Based on the single-cell RNA-Seq dataset, while type III and type VI collagen were found expressed in fibroblasts both from normal tissues and tumor tissues whereas type V collagen and XI collagen were found almost exclusively expressed in CAFs (tumor tissue). When further examining the CAF subtypes, type III collagen and VI collagen were found expressed in both myCAFs and iCAFs whereas type V collagen and XI collagen were found almost exclusively expressed in myCAFs and not iCAFs. Moreover, in the 220 patients, PRO-C3 and PRO-C6 was elevated in elevated in a few cancer types (p0. 05-0. 01) with an inter-patient variation ~2-fold whereas PRO-C5 and PRO-C11 were elevated in all cancer types (p0. 0001) with a ~5-fold inter-patient variation. These four biomarkers identified different pancreas cancer patients endotypes all with poor overall survival, P0. 001. In direct alignment, collagen pro-peptides we highly upregulated in cultures of CAFs. Conclusions: Profiling collagen expression in fibroblast from PDAC and NSCLC reveals that type V collagen and type XI collagen are exclusively found in myCAF not iCAF. Biomarkers of these collagens can be measured in serum from cancer patients and are prognostic for poor overall survival. Thus, these data suggest that cancer associated myo-fibroblast (myCAF) activity can be assessed non-invasively by specific collagen pro-peptide biomarkers. Citation Format: Nicholas Willumsen, Neel I. Nissen, Morten A. Karsdal. Serological assessment of cancer associated myo-fibroblast (myCAF) activity by collagen pro-peptide biomarkers provides high prognostic power abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 2027.