PTHLH and breast cancer: In this study, overexpression of PTHrP and loss of LIFR both enable otherwise dormant breast cancer cells to downregulate several quiescence- associated genes including thrombospondin-1 (TSP1) (90), transforming growth factor-β2 (TGF-β2) (91), tropomyosin-1 (TPM1) (92), and Selenbp1 (93), among others.