The invention belongs to the technical field of biological
medicine, and particularly relates to a biomarker of
prurigo nodularis and application of the biomarker. The invention discloses that
protease activated
receptor 2 (PAR2) regulates expression of Th2 type cytokines through a G alpha12-RhoA-ERK
signal channel for the first time, and further participates in morbidity of
prurigo nodularis (PN). According to the embodiment of the invention, various experimental means such as qRT-PCR,
Western Blot, IHC, IF and the like are utilized to verify expression up-regulation of PAR2 and related molecules in
skin tissues of a PN patient and the correlation of the PAR2 and related molecules with clinical symptoms. Molecules such as PAR2, RhoA, ERK, IL-4, IL-31 and the like are proved to be highly related to
pathological characteristics of PN. The molecules can be used as diagnostic markers or target spots for treating
prurigo nodularis, and can be used for early diagnosis of PN,
disease assessment or
drug development.