Considering malignancies, the duration of fever, particularly that lasting > 30 days, headache, hepatomegaly, splenomegaly, lymphadenopathy, anemia (hemoglobin [Hb] < 7 g/dL), and thrombocytopenia (platelet count < 150,000 cells/mm3) were associated factors, whereas cough was an inversely associated parameter similar to those in autoimmune diseases. This evidence concerns the gene GSTM1 and anemia (phenotype).