APOA2 and lung cancer: Consistent with the published data, our results indicated decreased levels of 31 complement and complement-related proteins (C1s, C4a/C4b, CFB, C3a, C5, C8b/C8g, C9, C1NH, C4BPA, CFH, CLU, VTN, VWF, SerpinC1, SerpinA3, MRC1, CD44, ApoA1, ApoA2, ApoA4, ApoB, ApoC1, ApoC3, ApoD, ApoE, A2M, SerpinA1, SerpinD1 and SerpinF1) and increased levels of 2 complement and complement-related proteins (C1QBP and SerpinH1) in lung cancer tissues compared to normal control tissues (Additional file 4: Figure S3 and Table S7).