The inhibitor of the SphK1 and SphK2 isozymes, SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl) thiazole)) induced proteosomal degradation of hSphK1a and hSphK1b in androgen-sensitive prostate cancer cells, however failed to promote degradation of hSphK1b in androgen-independent prostate cancer cells. This evidence concerns the gene SPHK1 and prostate cancer.