Isoenzyme pattern of enolase in human lung tumor xenografts in nude mice.

A simple method is described which allows easy determination of neuroendocrine (NE) differentiation in human broncho-pulmonary tumor models grown in heterotransplanted nude mice. Enolase (EC 4.2.1.11) isoenzyme composition is studied using the electrophoretic method in xenograft tumor homogenates. The relatively large amount of alpha gamma and gamma gamma isoenzymes (neuron-specific enolase (NSE] is indicative of the neuroendocrine differentiation level of these tumors. The gamma gamma isoenzyme is present at a high level (M +/- SE: 10 +/- 2%) in all NE tumor models and absent in non NE tumor models. The alpha gamma isoenzyme is found in a significantly higher proportion in NE tumor models (30 +/- 2%) than in non NE tumor models (9 +/- 2%) (p less than 0.001). Moreover it is possible to discriminate between human and mice isoenzymes to estimate the proportion of mouse tissue hat is present in the xenograft.