CASP9 and neoplasm: Based on the previous literature, we initially detected the protein expression pattern of CASP9 in the normal thyroid cell line (Nthy‐ori3‐1) and the TC cell lines (ARO, FRO and CAL‐62), which revealed that the CASP9 expression was lowered in the TC cell lines (Figure 4A), indicating CASP9 as a potential target of TC tumour cells.