For example, Notch1 inhibition in combination with a chemotherapeutic drug reduced CSC self-renewal in HNSCC CSCs in vitro and in vivo, confirming Notch1 as an ideal target for cancer treatments (Fukusumi and Califano, 2018; Venkatesh et al., 2018). Here, NOTCH1 is linked to head and neck squamous cell carcinoma.