However, while the addition of PEG-G-CSF with FOLFOXIRI plus Bev may be useful in preventing severe neutropenia or FN, there are currently few reports evaluating the efficacy of the PEG-G-CSF for neutropenia in mCRC patients administered FOLFOXIRI plus Bev and in the safety of PEG-G-CSF administered every 2 weeks. The gene discussed is CSF3; the disease is neutropenia.