CSF3 and bacterial infectious disease: Furthermore, the G-CSF value in case 1 was slightly above the upper limit (32.7 ng/L) of the reference value.[10] However, there are various, possible causes of elevated G-CSF and leukemoid reaction besides a GPT, such as a bacterial infection, myeloproliferative disease, and bone marrow metastasis.[19,21] Immunohistochemical analysis of the G-CSF was not performed in case 1, and multiple metastases had already developed before the increase in serum G-CSF was detected; thus, it is possible that the tumor was not producing G-CSF.