Rapamycin, an inhibitor of mTORC1, elongated primary cilia and inhibited proliferation of DU145, a human prostate cancer cell line. Rapamycin increased ciliogenesis of fibroblasts derived from patients with Lowe syndrome. Rapamycin increased ciliogenesis through upregulation of p27KIP1 in proliferating hTERT-RPE1 cells. This evidence concerns the gene CDKN1B and prostate cancer.