The reversed PGD2-mediated human hairs growth inhibition of DP-2 antagonists passes through the proliferation for reducing PGD2-triggered apoptosis and maintaining horn cell in a dose-dependent manner in vitro. Hair follicle shows that PGD2 influences the in-vitro method almost without neurological susceptibility from the baldness patient of about half. SNPs mankinds DP-2 genetic markers it is associated those by PGD2 hair growth inhibitions. These discoveries emphasize that role DP-2 regulating hair growths DP-2 is a kind of effective approach to this instruction, and the patient for preventing and/or treating androgen-dependent alopecia is sensitive to PGD2. It will benefit from treating moreover, SNPs identified here can be used to identify to suffer from.