The level of serum granulocyte colony-stimulating factor in cancer patients with leukocytosis.

The level of serum granulocyte colony-stimulating factor (G-CSF) obtained from patients with leukocytosis (greater than 10,000/microliters) between May 1989 and April 1991 was measured by enzyme immunoassay. Studied were 18 patients with malignant neoplasms (median age, 64 years) and 14 patients with hematologic disease (median age, 59 years). Increased serum G-CSF values ranging from 70 to 374 pg/ml were noted in 7 of 15 lung cancer cases, a case of malignant thymoma and a blastic crisis of chronic myelogenous leukemia. The rest of the cases showed a normal value (less than 60 pg/ml). There was no correlation between the neutrophil count and G-CSF level. In lung cancer cases with high G-CSF values, neither a characteristic histologic type nor common elevation of tumor markers could be seen. The neutrophil alkaline phosphatase score was significantly increased and hypercalcemia was presented in high G-CSF cases. G-CSF may contribute at least in part to unknown leukocytosis observed in malignant neoplasms, especially in lung cancer.