The boxplot displays significantly higherexpression levels of the PCNA-associated signature in tumor samples(red) compared to normal tissues (blue) across multiple cancers suchas breast invasive carcinoma (BRCA), head and neck squamous cell carcinoma(HNSC), lung squamous cell carcinoma (LUSC), and thyroid carcinoma(THCA) (Figure S2b). Here, PCNA is linked to head and neck squamous cell carcinoma.