RBBP8 and uterine carcinosarcoma: Moreover, RBBP8 promoter methylation was only present at low frequency in head and neck squamous cell carcinoma (9.6%, n = 46/481), lung squamous carcinoma (7.1%, n = 24/337), uterine carcinosarcoma (1.8%, n = 1/56), cervical squamous cell carcinoma (1.3%, n = 4/299), esophageal carcinoma (1.1%, n = 2/182), and lung adenocarcinoma (1.0%, n = 4/399).