IL6 and neoplasm: Significantly higher expression of the selected interleukins was observed in non-cancerous than tumour tissue, and IL-6 was significantly higher in the tumour tissue of patients with a history of ≤ 40 pack-years (PYs) (2.197, IQR: 0.821–4.415) than in those with > 40 PYs (0.461, IQR: 0.372–0.741; p = 0.037).