A. RNA extracted from primary human breast cancers and patient matched normal breast tissue demonstrates significantly higher mean RET expression in ERα-positive tumors compared to ERα-negative tumors and normal breast tissue. The data represent values from 20 ERα-positive, 10 ERα-negative tumors, and the 30 samples of matched normal breast tissue, which are overlaid for some data points. The p values were calculated using the Student’s t-test. B. When a cutoff of 0.5 fold RET expression relative to MCF-7 is used, significantly more ERα-positive tumors are RET positive compared to ERα-negative and normal breast tissue, p=0.001. The p value was calculated using the analysis of variation (ANOVA).