To examine whether C188-9 targeted STAT3 in other HNSCC cells, we used Luminex assays to determine the levels of constitutively phosphorylated STAT3 in 10 HNSCC cell lines (SCC-9, SCC-15, HN5, UM-SCC-1, SCC-61, SQ-20B, SCC-35, UM-SCC-17B, HN30 and HN31), as well as in the primary human esophageal epithelial cell line (HEEpiC). The gene discussed is STAT3; the disease is head and neck squamous cell carcinoma.