GDNF and breast carcinoma: At last, GDNF and ARTN and their receptors GFRα1 and Ret stimulate radio- and chemoresistance via autophagy, mitogenesis and neutralizing apoptosis, suggesting that they may be potential therapeutic targets for overcoming chemoresistance in the case of osteosarcoma, neuroblastoma, mammary carcinoma and glioblastoma [91].