Surprisingly and in contrast to diverse reports, which already demonstrated a positive correlation between IL-6 and CRP serum levels in patients with breast cancer or lung cancer, we did not detect significant correlations between IL-6 and CRP [33, 34] Two case reports of patients with TETs (TC and TNET) reported active secretion of IL-6 by neoplastic thymic epithelial cells. Here, CRP is linked to lung cancer.