This study demonstrates that an inflammatory response caused by the injection of
pristane into the peritoneal cavity of mice provides a useful system for rapid induction of myeloid
tumors by retroviruses. Two such
tumors, which developed in the peritoneal cavity with average latencies of 68 to 71 d and incidences of greater than 50%, are 1) the McML, mature monocyte-macrophage
tumors induced by retroviral constructs containing exons 2 and 3 of c-myc
cDNA, and 2) the MML, promonocytic
tumors induced by Moloney murine leukemia virus
infection and its integration into the c-myb locus. Development of both
neoplasms is clearly dependent on the intense i.p. inflammatory response, inasmuch as mice given the viruses and not
pristane fail to develop these
tumors. Although both types of
tumors appear in the peritoneal cavity, the MML
tumors that arise by i.v. injection of Moloney murine leukemia virus may actually originate via
infection, and perhaps transformation, of precursor hemopoietic cells outside the peritoneal cavity, followed by migration of the cells to the peritoneal cavity. This is suggested by the fact that i.v.v but not i.p. injection of virus is an efficient method of producing these particular myeloid
tumors. Although both McML and MML
tumors require the inflammatory environment for their development, treatment of mice with a nonsteroid anti-inflammatory
drug,
indomethacin, has no effect on McML monocyte/macrophage
tumors but completely prevents the development of the MML promonocyte
tumors.