PIM1′s upregulation in WHO grade 2 vs. grade 1 and in recurrent grade 2 vs. not recurrent grade 2 MNG, in necrotic vs. non-necrotic grade 2 MNGs, and in chromosome 1p and 22q-loss MNGs, as well as positive and negative correlation between its expression and Ki-67 and NF2 expression, respectively, suggest its oncogenic function in MNG. The gene discussed is NF2; the disease is toxic multinodular goitre.