GDNF and breast cancer: To address the clinical relevance of RET signaling, we performed a Kaplan-Meier plot analysis and found that high expression of RET was correlated with a worse prognosis for ERα+ BC patients treated with endocrine therapy, therefore further prompting this current study using TamS and TamR MCF-7 cells to elucidate the GDNF-RET signaling resistance mechanism.