In cases without DES exposure, approximately 50% showed microsatellite instability, but no mutations were found in the KRAS, HRAS, WT1, ER, or TP53 genes in these cases.[78] In 3 cases of HPV-negative CCC (clear cell carcinoma), Jenkins et al identified 1 TP53 mutation and 1 PIK3CA mutation.[28] Lee et al conducted genetic testing on a patient with cervical clear cell carcinoma and a history of intravaginal DES exposure. This evidence concerns the gene TP53 and cervical clear cell adenocarcinoma.