ANO1 and gastrointestinal stromal tumor: ANO1, also known as transmembrane protein 16A (TMEM16A) or gastrointestinal tumor protein 1 (DOG1), is a voltage-sensitive calcium-activated chloride channel that is frequently overexpressed in many kinds of tumors, including esophageal cancers, gastrointestinal stromal tumors, lung cancer, gastric cancer, breast cancer, prostate cancer, oral squamous cell carcinoma, pancreatic cancer, hepatocellular carcinoma and SCCHN cancer11–21; ANO1 has been used for GIST diagnosis in immunostained tissue specimens, even those specimens in which KIT is negative22–24.