IL6 and breast cancer: IL-6 has been identified as a cytokine abundantly present in the TME of various tumour types, including head and neck squamous cell carcinoma (HNSCC) [24,25,26,27], pancreatic cancer [28,29], non-small-cell lung cancer [30], breast cancer [14,31], ovarian cancer [19,32], and melanoma [33,34].