Te EGFR expression, with a magnitude of induction related to that for TSH (54). The expression of EGFR1 protein is drastically upregulated in PDTC and ATC, and absent or slight in normal thyroid gland and in papillary DTC, suggesting that upregulation of EGFR1 expression may be a molecular marker of dedifferentiation in thyroid epithelial carcinomas (56). High expression of EGFR is connected with lymph node metastasis in PTC and plays a function inside the progression of TC (53, 57, 58). It has been also reported that a patient with metastatic PDTC with an EGFR mutation responded to the treatment with the selective EGFR tyrosine kinase inhibitor (TKI) erlotinib (59). NH2-terminal lysine residues are acetylated on histones, and this way would be the principal one particular that controls the cellular differentiation and biological behavior of tumoral cells. The rising price in the gene transcription is due to a far more open chromatin configuration, while a closed chromosomal configuration results in transcriptional repression (48). In some cancer cells, the activity of histone acetyltransferase or histone deacetylase (HDAC) has been dysregulated (60). Vorinostat, depsipeptide, valproic acid, belinostat, and panobinostat have an antineoplastic effect on TC cells (61).Thyroid Cancer: Targeted TherapyOne in the most explored chemical template would be the pyrazolo[3,4d]pyrimidine (PP) heterocyclic core, shown to be a useful scaffold for the obtainment of productive TKIs (Table 1). Actually, derivatives belonging to this structural class show a large spectrum of activity. Distinct PP compounds act as: (a) Abl inhibitors and antiproliferative agents against human leukemia cell lines; (b) Src kinase inhibitors in neuroblastoma, medulloblastoma, and osteosarcoma; (c) phospholipase D inhibitors in unique neoplasias; and (d) urokinase plasminogen activator inhibitors, in breast cancer.RET PathwayFrontiers in Endocrinology | www.frontiersin.orgNovember 2015 | Volume six | ArticleFerrari et al.Aggressive Thyroid Cancer New TherapiesTABLe 1 | Principal involved pathways and relative targeted therapies in thyroid cancer. involved pathways Drugs Thyroid cancer PR Raf Sorafenib Sorafenib Sorafenib Vandetanib Vandetanib Vandetanib Motesanib Motesanib Axitinib Axitinib Sunitinib Sunitinib Cabozantinib Cabozantinib Pazopanib Lenvatinib Lenvatinib Vascular disrupting EGFR Histone deacetylase Combretastatin Gefitinib Vorinostat 30 DeTC 41 DeTC 207 DeTC 30 MTC 231 MTC 145 DeTC 93 DeTC 93 DeTC 91 MTC 49 DeTC 11 MTC 52 MTC 7 MTC 28 DeTC 11 DeTC 37 MTC 15 DeTC 37 DeTC 58 DeTC 261 DeTC 18 ATC 27 DeTC 16 DTC 3 MTC 0 23.NOTCH1, Human (HEK293, His-Avi) three 15 20 45 eight 14 SD 53.IFN-beta Protein Biological Activity 3 56 53 42 57 35 48 MTC 38 35 46 45 40 28 33 12 0 36 73 5 11.PMID:34235739 7 12.six 18.three 7.4 weeks three.7 Responses PD 7 PFS (months) 21 15 ten.eight 27.9 11.1 40 weeks 40 weeks DeTC 48 weeks MTC 18.1 16 12.eight 11.5 Gupta-Abramson et al. (62) Kloos et al. (63) Brose et al. (64) Wells et al. (65) Wells et al. (66) Leboulleux et al. (67) Sherman et al. (68) Bass et al. (69) Cohen et al. (70) Locati et al. (71) Carr et al. (72) D z et al. (73) Kurzrock et al. (74) Cabanillas et al. (75) Bible et al. (76) Cabanillas et al. (77) Schlumberger et al. (78) Cooney et al. (79) Pennell et al. (80) Woyach et al. (81) AuthorsVEGF3830 35 28 PR + 3 CR 18 PR + 9 CR 29 53 49 50 63 PR + 2717 27ATC, anaplastic thyroid cancer; DeTC, dedifferentiated thyroid cancer; MTC, medullary thyroid cancer; PR, partial response; PD, progressive disease; PFS, progression-fre.