Tumors that express keratin include carcinomas, thymomas, sarcomas and trophoblastic neoplasms. Malignant phyllodes tumours behave like sarcomas and can develop blood-borne metastases. Non-epithelial malignancies such as melanomas and sarcomas are even more rare. GISTs are tumors of connective tissue, i.e. sarcomas; unlike most gastrointestinal tumors, they are nonepithelial. It is rarely found in some sarcomas, such as Kaposi's sarcoma, and carcinomas. Soft-tissue sarcomas are relatively uncommon cancers. Most fusion genes are found from hematological cancers, sarcomas, and prostate cancer. They cause various sarcomas, leukemias and immune deficiencies in mammals, reptiles and birds. Some tumors may be difficult to biopsy, such as sarcomas. Research into hormonal treatments for endometrial stromal sarcomas is ongoing as well. Survival is better compared to other types of uterine sarcomas. Soft-tissue sarcomas are the most common cancer types. This is comparable to other high grade uterine sarcomas . It is also undergoing clinical trials for the treatment of breast, prostate, and paediatric sarcomas. Numerous studies using it to treat soft tissue sarcomas including GIST are ongoing.