Fig. 2

OPLS-DA score plots for the NILM and SIL groups (A) and the LSIL and HSIL groups (C). Panels (B) and (D) present the results of the corresponding 1000 permutations (p < 0.001), indicating the reliability of the permutation tests. For the NILM and SIL comparison, panel (B) shows R2Y = 0.558 and Q2 = 0.296, while panel (D) for the LSIL and HSIL comparison shows R2Y = 0.977 and Q2 = 0.673. Here, R2Y indicates the proportion of variance explained by the current model, while Q2 represents the proportion of data variance that the model can predict.