HOXD9 and thyroid gland papillary carcinoma: Subsequently, an examination was conducted to assess the expression of HOXD9 in various subtypes of THCA, including 11 cases of ATC, 49 cases of papillary thyroid carcinoma (PTC), and 45 cases of normal thyroid from the Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc = GSE33630) and discovered that HOXD9 expression is significantly higher in ATC and PTC than in the normal control group (Additional file 1: Figure S1C, D).