UCN2 and systemic sclerosis: To further analyze the role of SRP-related genes in SSc-PH, we performed unsupervised clustering of the PBMC samples from SSc-PH patients in the training set using the expression values of 30 DE-SRPGs with the R package, “ConsensusClusterPlus.” The consensus matrix indicates that at k = 2, the number of patients in each cluster was equally distributed, none of the clusters contained abnormally high or abnormally low numbers of patients, and the correlation between the two clusters was low (Figure 3A).