Briefly, GRP78 can predict patient grades and metastasis [180]; SAA2 and CFB were associated with patient recurrence, where combining Fuhrman grade with CFB levels showed the best C-index to predict recurrence [187]; IL-6 and IL-27 can predict recurrence of RCC, but as with survival prediction their abilities to predict recurrence vary across tumor sizes [117]; plasma immune checkpoints, including PD-1, PD-L1, and BTN3A1, can predict metastasis, which is correlated with the number and location of metastases [188]; and urinary PLIN-2 levels can predict tumor size [186]. The gene discussed is IL6; the disease is renal cell carcinoma.