Altered expression of acute-phase reactants in mouse liver tumors.

We studied the expression of eight liver acute-phase genes in spontaneous and diethylnitrosamine-induced mouse liver tumors (MLTs) under basal and induced conditions. Primary spontaneous and chemically induced MLTs were used for RNA isolation and histopathologic analysis. In the noninduced state, all MLTs showed similar levels of mRNA for albumin, serum amyloid A, alpha 1-acid glycoprotein, haptoglobin, and alpha-, beta-, and gamma-fibrinogens compared with control or background livers. The mRNA for the alpha 1-major acute-phase protein, however, was consistently elevated in both spontaneous and diethylnitrosamine-induced MLTs. The expression of these acute-phase reactants in 11 MLTs was examined following exposure of the mice to turpentine. The relative expression of these mRNAs in these MLTs varied widely compared with mRNA expression in controls. Though all MLTs expressed the same three species of fibrinogen mRNAs as did the controls, no MLT demonstrated downregulation of albumin mRNA levels, and only 1 of 11 MLTs showed a marginal increase in serum amyloid A mRNA levels. Synthesis of mRNA for alpha 1-acid glycoprotein and haptoglobin was intermediate. The study of the response of MLTs to specific acute-phase stimuli may make possible a better understanding of the basis for coordinated expression of acute-phase reactants and of the variable phenotypes associated with cancers.