NOTCH1 and Intervertebral disk degeneration: To examine the expression differences of hub genes in intervertebral disc degeneration samples, we used the R package “ConsensusClusterPlus” to identify different subtypes related to intervertebral disc degeneration based on the expression of nine hub genes (RCOR2, STAT3, NOTCH1, SP1, SART1, PRIM1, LYAR, KIF20B, MSH2) in the merged dataset, and finally identified two subtypes: Cluster 1 and Cluster 2 (Figure 5A).