The correlations between monocytes and lymphopenia were seldom studied, but macrophage, which differentiated from monocyte, leads to either radiosensitization or radioresistance depending on different tumor types or different radiation regimen studied, and various molecular players as NF-kB, MAPKs, p53, reactive oxygen species, and inflammasomes that have been involved in these processes (28), which might mention the monocyte reduction correlated to lymphopenia at some extend. The gene discussed is NFKB1; the disease is lymphopenia.