The Invention relates to a nucleic acid and proteins of tumors and neoplasias of the thyroid gland. Said nucleic acid comprises a nucleic acid sequence selected among the group consisting of SEQ ID No. 1, 3, 4, 9 and SEQ ID No. 11 to 16. The invention also relates to fusion proteins observed in tumors and neoplasias of the thyroid gland, said fusion proteins containing an amino acid sequence according to SEQ ID No. 2, SEQ ID No. 5 to 8, 10, and 17.