High incidence of stomach cancer in relatives of patients with malignant lymphoproliferative disorders.

Family histories of 189 patients with lymphomas and leukemias and 14 patients with stomach cancer were used in this study. Controls consisted of family histories of 391 patients with other tumors. In the 189 probands with lymphoproliferative disorders stomach cancer accounted for 17.3% of the total cancers in the relatives, whereas in the probands with breast and other types of cancer the corresponding figures were 8.1% and 8.3% as against an incidence of 5.9% of stomach cancers in Basel. In first-degree relatives, the incidence of stomach cancer was higher than expected in the families of probands with malignant lymphoma and stomach cancer. It is suggested that an inherited subclinical disturbance of the immune system is involved in familial association of stomach cancer with malignant lymphoproliferative disorders.