[Myelodysplastic syndrome associated with gastric cancer and colon polyp].

A 62-year-old man was found to have myelodysplastic syndrome (MDS) and gastric cancer. Serum studies revealed hypogammaglobulinemia, and positive reactions to rheumatoid test and anti-nuclear antibody. Chromosomal analysis of the bone marrow revealed deletions of No. 5 and 7 chromosomes and that of the stomach showed complex abnormalities. It may be hypothesized that an initial event which selects a clone of stem cells could manifest with this sort of immunological abnormalities. Subsequent deranged immunosurveillance may be responsible for the increased risk of cancer. Alternatively an increased chromosomal instability which seems to be associated with immunodeficiencies might be responsible for cancer development.