A combination of dietary protein depletion and PHA-induced gut growth reduce the mass of a murine non-Hodgkin lymphoma

The results presented in this study show that a switch from a non-protein d iet (NPD) to one of a normal protein content (LA) on the day of subcutaneou s injection of non-Hodgkin lymphoma tumour cells greatly favoured the devel opment and growth of the tumour. Interestingly, however, inclusion of the p lant lectin phytohaemagglutinin (PHA) in the LA diet appeared to compete wi th the effect of switch to the protein-rich diet, resulting in decreased tu mour size and an increased incidence of necrosis. PHA was shown to induce h yperplasia of the gut even in the presence of the growing tumour. This obse rvation together with the fact that gut hyperplasia also occurred in animal s which were fed NPD supplemented with PHA, indicated the strength of PHA a s a growth signal. It would seem likely that this 'normal' growth is able t o compete with the tumour for important growth factors and nutrients, inclu ding polyamines, effectively starving the tumour for these molecules and re sulting in its decreased rate of proliferation, (C) 1999 Elsevier Science S .A. All rights reserved.