BCL2L1 and in situ carcinoma: However, there is very limited available information on the expression of Bcl-xL in oral premalignancy; Schoelch et al. [55] reported that Bcl-X (including both splice variants Bcl-xL and Bcl-xS) demonstrated immunohistochemical positivity in 70% of hyperkeratotic and mildly dysplastic lesions and 85.7% of moderate/severe dysplasias and carcinomas in situ, concluding that this molecule is expressed early in the process of oral carcinogenesis.