CASP6 and head and neck squamous cell carcinoma: By consulting the UALCAN and Human Protein Atlas databases, we found that BIRC5 (survivin), BIRC2, and CASP6 (all downregulated by HCQ in Ca9-22 cells) are overexpressed in head and neck squamous cell carcinoma (HNSCC) tissues compared to normal tissues, with expression levels increasing across tumor stages.