Table 1.

Examples of cytokine signalling in cancer and its effects on cancer cell behaviour.

Cytokine	Cancer Type	Observed Effects
IL-1β	Colorectal Carcinoma	Promotes cancer stemness and invasiveness through the activation of Zeb1, a protein associated with the epithelial-mesenchymal transition (EMT) [72].
IL-17	Colorectal Carcinoma	Overexpressed by tumour-associated macrophages (TAMs) and Th17 (helper T cells) [73]. Associated with an inflammatory microenvironment characterized by high microvessel density and VEGF-mediated angiogenesis by the cancer cells. IL-17 expression levels were found to be a statistically significant factor correlated with patient survival rates [73].
IL-6	Colorectal Carcinoma	T helper type 17 (Th17)-associated cytokine. Produced in large amounts by tumour infiltrating leukocytes, inducing STAT3 and NF-kB-induced cancer cell growth [74].
	Osteosarcoma	Induces increased expression of intercellular adhesion molecule-1 and increases cancer cell migration, as mediated by the integrin-linked kinase (ILK/Akt/AP-1) pathway (IKL and Akt activate AP-1) [75]. This contributes to the metastatic potential of these cells by increasing migration and contributing to anchorage-independence of cell colonies by allowing them to attach to each other rather than the ECM [75].
IL-8	Carcinoma (breast, lung, pancreatic)	Proinflammatory CXC cytokine implicated in the EMT and, thus, the induction of invasive behaviours in tumours [76].
	Melanoma	When expressed by tumour cells, promotes tumour cell motility, proliferation, and survival in an autocrine manner, while inducing the angiogenesis of epithelial cells and the recruitment of tumour-associated neutrophils (TANs) to the tumour in a paracrine manner [77]. This is an important example of a tumour-secreted factor influencing both tumour behaviour and the behaviour of the noncancerous tumour stroma [77].
TNFα	Melanoma, Breast Carcinoma	Expressed by TAMs. Shown to be important determinant of the migratory behaviours of cancer cells, and thus their propensity for invasive behaviour [41].
	Colorectal Carcinoma	T helper type 17 (Th17)-associated cytokine. Produced in large amounts by tumour infiltrating leukocytes, inducing STAT3 and NF-kB-induced cancer cell growth [74].
TGF-β	Melanoma, Breast Carcinoma	Expressed by TAMs. Shown to be important determinant of the migratory behaviours of cancer cells, and thus their propensity for invasive behaviour [41].