CCND2 and obstructive sleep apnea syndrome: According to the expression profiling analysis of the GSE135917 data set, the expressions of CCND2, WT1, E2F2, and IRF1 in the OSA group were significantly decreased (p < 0.05), while there was no significant difference in BAZ2A, LAMC1, and DAB2 (p > 0.05) (Table 3).