NGFR and carcinoma: The distribution of cells expressing p75ICD and/or p75NTR FL, and their eventual co-localization with ABGC2, was also analyzed in each LSCC specimen by differentiating four distinct zones in the tumor sample, corresponding to: normal epithelium (1), aberrant epithelium (2), the carcinoma invasive front (3), and carcinoma in situ (4) (Figure S3).