Fig. 5

ECM alterations in CXPA tumorigenesis and stiffness measurements of PA and CXPA. (a) Macroscopic appearance of surgically resected CXPA with SDC tissue specimen. Scale bars = 5 mm. (b) H&E staining results of CXPA tissue in the black frame in Figure (a) Scale bars = 1000 µm. Hyaline changes are shown in (H) of (b) Scale bars = 100 µm. A malignant area is shown in (M) of b. Scale bars = 20 µm. Red arrowheads indicate carcinoma extending beyond the pleomorphic adenoma capsule. The image of perineural invasion as an insert section in (M) of b. N represents the nerve, and the black arrowhead indicates the presence of invasive cancer cells. (c) TEM images of hyalinized area in CXPA. (Left) collagen in TEM transverse section. Scale bars = 100 nm; (right) collagen in TEM longitudinal section, the collagens have a typical near-circular profile. Scale bars = 250 nm. (d) Overview of PSR staining of CXPA and PA specimens. Positive regions under a polarized light microscope were in bright orange (black arrowhead). Scale bars = 50 µm. (e) Alignment index (AI) confirmed a higher degree of collagen fiber alignment in CXPA compared to PA tissues (n = 3, respectively). (f) Scatter plot of collagen cross-links of PA (n = 5) and CXPA (n = 5) specimens. (g) H&E staining of PA and CXPA clinical samples. Scale bars = 100 µm. (h) Protein expression of COL1A1, IGFBP5, and DCN in CXPA and PA clinical specimens. Scale bars = 50 µm. (i) Shear wave elastography (SWE; top) and B-mode (bottom) images on split screen mode of PA. (j) Shear wave elastography (SWE; top) and B-mode (bottom) images on split screen mode of CXPA. k. H&E staining of ECM-rich regions in PA and CXPA specimens. Scale bars = 200 µm. l. AFM topography images of PA (top) and CXPA (bottom). Scale bars = 2 µm. m. Maps of E-moduli of PA (top) and CXPA (bottom). Scale bars = 2 µm. n. Mean E-modulus of ECM-rich regions of PA and CXPA. ^*p < 0.05, ^***p < 0.001, ^****p < 0.0001. Student’s t-test. Error bars indicate mean ± SD.