Fig. 3

Establishment of the diagnostic gene signature by LASSO COX regression analysis. A LASSO COX regression for 9 sulfur-associated genes. The coefficient profile plot was generated against the log (lambda) sequence (Upper). LASSO coefficient profiles of the nine genes in the merged dataset (Lower). B Accuracy of the diagnostic model for the six-gene signature to predict OA diagnosis, as evidenced by the receiver operating characteristic (ROC) curve analysis. When AUC (i.e., Area under the ROC curve) is 0.5, it means there is a 50% chance that the model can distinguish between positive and negative classes; 0.7 ≥ AUC > 0.6: acceptable discrimination; AUC > 0.7: excellent discrimination. C Detailed diagnostic information (healthy/OA) and expressional patterns of candidate genes differ between high-risk score and low-risk score groups. Upper layer: level of risk score for each sample; middle layer: OA status (red: OA, green: healthy); lower layer: heatmap shows the gene expression. D The boxplot shows differential expression levels of the six genes between healthy and OA groups