In line with previous observations about IL-8 upregulation in the presence of GDNF+GFRα1 in SK-N-MC neuroectodermal tumor cells, stably transfected with the human RET gene, as well as in TT medullary thyroid carcinoma cells and PTC-1 papillary thyroid carcinoma cells [49,50], we sought to verify whether RET could induce IL-8 also in BC cell lines. This evidence concerns the gene GFRA1 and breast cancer.