SOX2 and head and neck squamous cell carcinoma: Three sgRNAs for SOX2 (sgSOX2‐A, ‐B, and ‐C) were screened in HNSCC cell lines with different HNSCC primary origins (UMSCC‐104, FADU; Figure1A) by comparing gene‐editing efficiency after transfection with Cas9 protein and sgRNAs for SOX2 (Ribonucleoprotein/ RNP complex).