Using flow cytometry, we first analyzed the numbers of the total T cells (CD3+), T helper cells (CD3+CD4+), cytotoxic T cells (CD3+CD8+), NK cells (CD56+CD3−), NK T cells (CD56+CD3+), NK CD4+ T cell subsets (CD56+ CD3+CD4+), and NK CD8+ T cell subset (CD56+CD3+ CD8+) populations in the fresh blood samples from lung cancer patients (before, during and after) induction of chemotherapy as compared to control subjects. The gene discussed is CD4; the disease is lung cancer.