In matched samples, the level of the MCR1 protein was reduced in cancer tissues but increased in plasma from patients with lung cancer [5] (Fig. 1); 3) We failed to determine the levels of 3 complement mRNAs, 10 complement proteins and 4 complement-related proteins in lung cancer tissues, and 30 complement proteins in serum due to the limited data available in public databases (Table 1 and Additional file 4: Table S4). The gene discussed is VTN; the disease is cancer.