Source:http://linkedlifedata.com/resource/umls/id/C0037994
MSH: Strains of MURINE LEUKEMIA VIRUS that are replication-defective and rapidly transforming. The envelope gene plays an essential role in initiating erythroleukemia (LEUKEMIA, ERYTHROBLASTIC, ACUTE), manifested by splenic foci, SPLENOMEGALY, and POLYCYTHEMIA. Spleen focus-forming viruses are generated by recombination with endogenous retroviral sequences.,NCI: Defective virus found in certain strains of Friend virus, detected by its ability to form foci in spleens of mice and believed to be responsible in those strains for the production of a leukemia associated with polycythaemia rather than anemia. (DictionaryBarn.com)