CD34 and atrial fibrillation: Cystic degeneration is one of the predictors of gastrointestinal stromal tumors with high malignant potential (14).GIST can usually express CD34, CD117, DOG-1, in immunohistochemical results, and some cases can also express S-100, SMA, while β-catenin is usually not expressed (15).It has been reported in the literature that GIST and AF may be susceptible and can be combined (16).