The present study aimed to investigate the miRNome of different leukocyte subpopulations, including eosinophilic and neutrophilic granulocytes (CD15+), monocytes (CD14+), B-cells (CD19+), T-cells (CD3+), and natural killer (NK) cells (CD56+), to investigate the origin of the lung cancer specific miRNA expression pattern that is known for whole blood. The gene discussed is NCAM1; the disease is lung cancer.