Patients diagnosed with cancer within 3 months had higher plasma CRP (p < 0.001), IL‐6 (p < 0.001), YKL‐40 (p < 0.001), CA 19‐9 (p < 0.001), CEA (p < 0.001), CA‐125 (p = 0.0075) and PSA (p < 0.001) than patients not diagnosed with cancer. Here, IL6 is linked to cancer.