In PA and RPA, PCNA-positive staining was mainly localized in the epithelial cells of glandular structures, as well as in the fibroblast-like spindle cells of fibrotic structures, whereas in CXPA, PCNA-positive staining was mainly localized in cancer cells of malignant structures and to some extent in CAF-like cells. The gene discussed is PCNA; the disease is cancer.