A 45-year-old man was noted to have a new onset thrombocytosis with a PTL count of 526 × 109/L and normochromic, normocytic mild anemia (Hb 10.5 g/dL), whereas the white blood cell (WBC) count (8.02 × 109/L) was within the normal limit with 63% neutrophils, 27% lymphocytes, and 8% monocytes. This evidence concerns the gene GSTM1 and anemia (phenotype).