Furthermore, three of the studies included in this meta-analysis have shown, in oral squamous cell carcinomas, oral lichen planus and keratocystic odontogenic, that tissues with overexpression of SP/NK-1R also showed a high expression of Ki-67 [11,28,47]; similar findings have also been reported through Ki-67 labeling index assessment in other human cancers, such as Hepatoblastoma [48] or leukemia [49]. Here, TACR1 is linked to oral lichen planus.