Analysis of fibrillar collagen structure in human HNSCC stroma confirmed the correlation observed in the bioinformatics analysis between ECM production and a myofibroblastic non-senescent stroma: p16-negative/SMA-positive tumors displayed elongated collagen fibers which were absent in the p16-positive/SMA-positive stroma (Supplementary Fig. S5D-F). Here, SMN1 is linked to head and neck squamous cell carcinoma.