Unresolved chronic inflammation predisposes tissues to tumorigenesis, and it represents a high risk factor for many cancers such as hepatocellular carcinoma (HCC). Besides, even if not all cancers emerge within an inflammatory context, such as breast cancer, all solid tumours lead to some degree of tumour-elicited inflammation. Therefore, inflammation is now accepted as a hallmark of cancer. Interleukin 6 (IL-6) family is considered one of the most important cytokine families in the link between inflammation and cancer progression, and dysregulation of its family member Oncostatin M (OSM) has been linked to inflammatory diseases, fibrosis and cancer. This work sought to determine the contribution of OSM signalling to cancer-promoting inflammation, and to dissect the molecular mechanisms downstream OSM to find key mediators and potential therapeutic opportunities for intervention within the OSM pathway. Using a wide array of in silico, in vitro and in vivo models, the data provided herein support that OSM signalling pathway is a promising therapeutic target in ER- breast cancer patients and that it has a therapeutic potential for HCC even if further investigation is required.