The present disclosure provides RNA technologies for targeting Claudin-18.2 polypeptides. In some embodiments, such RNA technologies can be useful for treatment of diseases associated with positive expression of Claudin-18.2. For example, in some embodiments, such RNA technologies can be useful for treatment of Claudin-18.2 positive cancer, including, e.g, but not limited to biliary cancers, ovarian cancers, gastric cancers, gastro-esophageal cancers, pancreatic cancers. In some embodiments, such RNA technologies can be used in combination therapy (e.g, in combination with a chemotherapeutic agent).