The analysis of genes with expressions that correlated with both ccRCC and obesity revealed five candidates: immunoglobulin heavy constant alpha 1 (IGHA1) and immunoglobulin κ constant (IGKC), which act as oncogenes, as well as monoamine oxidase A (MAOA), mucin-20 (MUC20) and transient receptor potential melastatin 3 (TRPM3), being tumour suppressor genes. The gene discussed is MAOA; the disease is nonpapillary renal cell carcinoma.