TP53 and ovarian serous adenocarcinoma: Another precursor lesion even earlier than STIC is the p53 signature lesion (p53 signaling pathway), characterized by the growth of cells in the distal portion of the tubal fimbria that shares properties with serous ovarian cancer - including p53 mutations - and is a precursor to HGSC.32The p53 signature are extremely small lesions represented by 10-30 cells.