[Genetic analysis of precancer-cancer of the stomach system. II. Lactate dehydrogenase in families of the patients: is it a marker of hereditary predisposition?].

The possibility of using the LDH as a marker of hereditary predisposition to the stomach cancer was analysed by using the genetical correlational analysis. The LDH isoenzymes in the gastric body were studied in 56 pedigrees. Similar LDH alterations were detected in relatives with cancer and precancer (ulcer disease, atrophic gastritis). Relatives with no such pathology had LDH isoenzymes, similar to the control individuals. High and significant coefficients of phenotypic and environmental correlation of LDH and predisposition to the stomach cancer were obtained. The coefficient of genetic correlation was not significant. The problem of the origin of these LDH variances is discussed. The preliminary conclusion is that the LDH isoenzyme changes revealed in patients with stomach cancer appear as a consequence of the disease, and cannot be used as the marker of hereditary predisposition.