Studies using targeted gene deletion, RNA interference or inducible expression have shown that Mcl1 is essential for the growth of diverse tumors, including acute myeloid leukaemia [6], lymphomas [7], papillary thyroid carcinoma [8], breast cancers [9], oral squamous cell carcinomas [10], and non-small-cell lung carcinoma [11]. Here, MCL1 is linked to thyroid gland papillary carcinoma.