Spatial profiling of a unique cancer-associated fibroblast population in the tumor microenvironment in sporadic early-onset colon cancer [eocc]

The incidence of sporadic early-onset colon cancer (EOCC) has increased worldwide. The molecular mechanisms in the tumor and the tumor microenvironment in EOCC are not fully understood. The aim of this study is to unravel unique spatial transcriptomic and proteomic profiles in tumor epithelial cells and cancer-associated fibroblasts (CAFs). Sporadic colon cancer FFPE tissue samples were divided into patients diagnosed with EOCC (<50 yrs) and late-onset colon cancer (LOCC, ≥50 yrs). Spatial transcriptomic analysis of 112 areas of interest (AOIs) were performed using Nanostring GeoMx digital spatial profiling. The data generated was combined with in silico analysis and functional assays to characterize FAP(+) CAFs at the EOCC tumor invasive margin. Eight CC FFPE tissue samples were analyzed by NanoString GeoMX Digital Spatial Profiling. Four FFPE tissue samples were from EOCC, and four samples were from LOCC patients. The regions of interest (ROI) were collected in each tissue samples and segmented in areas of interest (AOIs) based on the staining pattern of three fluorescently labeled cell type specific morphological markers: PanCK+, Vim, and FAP. In addition, histological regions in the FFPE tissues were pathology-defined as tumor center (TC), tumor invasive margin (TIM), and adjacent normal (AN) tissue areas.