However, when the expression of Axl predominates, prostate cells remain largely quiescent.42 These findings suggest that a balance between the expression of Axl and Tyro3 is associated with a molecular switch between a dormant and a proliferative phenotype in prostate cancer metastases.42 Similarly, the differential expression of Axl and Gas6 in renal cell carcinoma reflects tumour advancement and survival.12 Serum levels of soluble Axl and Gas6 protein and Gas6 mRNA level correlate with survival, metastasis and disease severity. This evidence concerns the gene GAS6 and Familial prostate cancer.