BTC and breast cancer: Among the transcripts up-regulated in the mammary gland of HF heifers were also: fibroblast growth factor 2 (FGF2), which was shown to play an important role in the differentiation of stem cells to mesodermal lineages (Sharpe et al. 2011); betacellulin (BTC), linked with the development of a lactating-like phenotype in the mammary gland of virgin female mice (Dahlhoff et al. 2011); nerve growth factor (NGF), involved in mammary tumor stem cell metastasis, proliferation, and survival (Adriaenssens et al. 2008) (Table 1).