Social stress influences tumor growth

Growth of syngeneic P815 mastocytoma in DBA/2J male mice was evaluated following social and physical stress exposure. Although social isolation following tumor cell transplantation enhanced tumor growth, it appeared that it was the abrupt change in social conditions, rather than the isolation per se which was responsible for the exacerbation of tumorigenicity. Moreover, it was found that the animals' behavior after social change could modify this effect. If mice engaged in persistent fighting, the tumorigenic consequences of social change were not apparent. In addition, it was observed that social conditions interacted with physical stress. Footshock enhanced tumor growth among group housed mice, but retarded tumor development among socially isolated mice.