HHLA2 and dysplasia: The quantification and statistical analysis of the staining patterns of HHLA2 and TMIGD2 in the normal mucosa, dysplasia, and OSCC samples revealed that the HHLA2 expression level was continuously and significantly increased in the dysplasia and OSCC samples (Figure 1(b)), while the TMIGD2 expression level was continuously and significantly decreased in the stroma of the dysplasia samples and in the stroma of the OSCC samples (Figure 1(c)).