MSLN and pharyngeal squamous cell carcinoma: In the study with the several cell lines, MSLN was mildly expressed in the A-253 cells compared with the K562-MSLN cells and M108 cells those were positive controls, whereas the expression level in the A-253 cells was remarkably higher than that observed in the IMC-3 cells (derived from human maxillary squamous cell carcinoma) or FaDu cells (derived from human pharyngeal squamous cell carcinoma) (Fig. 1i and Additional file 1: Figure S1).