Unfortunately, we could estimate the RET level only in 21 samples, namely those that returned assessable and reliable levels of the beta-2-microglobulin housekeeping, besides RET. Despite this was not enough to draw a genotype-phenotype correlation, we could obtain RET expression data which overall confirmed the expression of this gene in the BC tissues collected (Supplementary Information file and Figure S3). This evidence concerns the gene B2M and breast cancer.