Fig. 6.

Raman spectra differences among different subgroups and corresponding biological origins. A, E, I, 3D PCA image, B, F, J, Average Raman spectra and PC loadings, C, G, K, RF important maps (same color assigned to same Raman peaks) and D, H, L, PC fitting diagrams of PD-L1_Gversus PD-L1_L, PD-L1_Gversus PD-L1_Tversus PD-L1_M and PD-L1_Lversus normal brain tissue, respectively. The grey regions in B, F, and J indicate the differential Raman peaks extracted by RF. The red and green in D, H, and L mark the major contributive biomolecules in the positive and negative directions in PC loadings, respectively. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)