Predicted to be involved in chemical synaptic transmission. Located in extracellular exosome. Most malignant cells exhibited moderate cytoplasmic immunoreactivity. Malignant melanomas, urothelial cancers and a few cases of gastric adenocarcinomas demonstrated strong cytoplasmic positivity. Malignant gliomas, breast, prostate, testis and skin cancers displayed weak staining or negative cells in several cases.