TMPRSS2 and Familial prostate cancer: In vitro models suggest that YAP1 induces growth and migration in normal prostate epithelial cells5, revealed functional relationships between YAP1 activity and the prostate cancer specific TMPRSS2:ERG gene fusion23 as well as the PTEN tumour suppressor24, which is lost in about 20% of prostate cancers25, and that interaction of YAP1 with the androgen receptor may contribute to the development of castration-resistant prostate cancer26.