With fresh surgical lung cancer tissue, we performed LMD to capture cancer cells and normal lung epithelial cells adjacent to cancer nests only without lymphocytes (Figure 5, A) to detect the mRNA transcripts of IgG including IGHG1, κ constant (Cκ), λ constant (Cλ), γ variable (Vγ), κ variable (Vκ), λ variable (Vλ), sterile germ line transcripts (Iγ-Cγ) and essential enzymes including RAG1, RAG2 and AID for immunoglobulin synthesis and class switching. The gene discussed is RAG1; the disease is lung cancer.