CASP3 and head and neck squamous cell carcinoma: Cleaved caspase-3 IHC was performed for three (n = 3) HPV-driven HNSCC (HNSCC9, HNSCC10 and HNSCC13) for primary and 3D-OTC, revealing a strong increase of the apoptosis marker over time in two (n = 2/3) HNSCC (HNSCC9 and HNSCC10) and stable cleaved caspased-3 expression in one (n = 1/3) sample (HNSCC13) (Figure S4).