TP53 and adenoma: Four main theories have been proposed: CAC, due to the finding of transition areas between typical CAC and SRCC in many cases[11]; adenoma, typically reported as a combination of adenoma cells and signet ring cells, just as this case[11–15]; atypical epithelium, which is associated with p53-positive intraepithelial signet ring cells[11]; and a combination of these lesions.