ESR1 and squamous cell carcinoma: High EpCAM staining was linked to high grade (p < 0.0001), distant metastasis (p = 0.0006), ER/PR loss (p < 0.0001 each), and HER2 positivity (p = 0.0009) in breast cancer of no special type, as well as to high grade and to HPV infection in squamous cell carcinomas of different sites (p < 0.0001 each; Table 2 and Supplementary Table S3).