TNF and renal cell carcinoma: Furthermore, tumor-derived factors may influence host nutritional status.[30] [33] Tumor-derived tumor necrosis factor-alpha (TNF-α) promotes progression and epithelial-mesenchymal transition in RCC cell lines.[34] Because TNF-α is a key regulator of cancer cachexia, we postulate that undernutrition may be associated with high concentrations of this tumor-derived cytokine in peripheral blood, which also indicates highly aggressive tumors.