NOTCH1 and head and neck squamous cell carcinoma: NOTCH1 signaling was characterized in three HPV-positive (UD-SCC-2, UP-SCC-154, 93VU) and nine HPV-negative (UD-SCC-3, -4, -5, -6, -7, UP-SCC-111, HN, Cal27, and SAS) HNSCC cell lines with Western blotting (Figure 5).