RBP1 and head and neck squamous cell carcinoma: Next, we analyzed the expression of CRBP-1 in TSCC and HNSCC in the multiple cancer microarray data sets available from Oncomine (http://www.oncomine.org), and found that the mRNA expressions of CRBP-1 in TSCC and HNSCC tissues were markedly higher than those in the matched normal non-tumorous tissues, and some normal tissues had very low CRBP-1 expression with a negative value (Fig. 1b and c).