Blocking solution

The paraffin‐embedded tissue sections were deparaffinized in xylene, rehydrated in ethanol, and immersed in citrate‐NaOH buffer (10 mmol/L sodium citrate, pH 6.0) at 121°C for 20 minutes. After retrieval of antigenicity, the nonspecific Ab reaction was blocked in blocking solution (PerkinElmer Life Sciences), and the samples were incubated with Abs against HA (3F10; Roche Diagnostics), E‐cadherin (610181; BD Biosciences), and Ki‐67 (Abcam). After the sections had been washed, the reacted Abs were detected using the Dako EnVision+ System/HRP (DAB) (DakoCytomation).

Paraffin‐embedded tissue sections were deparaffinized in xylene, rehydrated in ethanol, and autoclaved for 20 minutes in citrate‐NaOH buffer at 121°C for antigenicity retrieval. After suppression of nonspecific antibody reactions in blocking solution (Perkin Elmer Life Science), samples were incubated with primary antibodies. For immunohistochemical (IHC) staining, reacted antibodies were detected by the Dako EnVision + System/HRP (DAB, DakoCytomation). For quantitative analysis we used NanoZoomer Digital Pathology system (2.0RS, Hamamatsu) and the QuPath.³³ For immunofluorescence (IF) staining, samples were then incubated with secondary fluorescently labeled antibodies and mounted with DAPI Fluoromount‐G^® (SouthernBiotech) for nuclei staining. We used a fluorescence microscope (Keyence BZ‐X710) for detection and imaging. Antibody information is listed in Table S2.

The paraffin‐embedded tissue sections were deparaffinized in xylene, rehydrated in ethanol, and immersed in citrate‐NaOH buffer (10 mmol L⁻¹ sodium citrate, pH 6.0) at 121°C for 20 minutes. After retrieval of antigenicity, the nonspecific antibody reaction was blocked in blocking solution (Perkin Elmer Life Science), and the samples were incubated with antibodies against E‐cadherin (610181, BD Biosciences, 1:100) or Ki‐67 (ab15580, Abcam, 1:500). After the sections had been washed, the reacted antibodies were detected using the Dako EnVision + System/HRP (DAB) (DakoCytomation).