There is a feedback loop between α5‐nAChR and Stat3 that contributes to the nicotine‐induced tumour cell proliferation.18 α5‐nAChR modulates lung tumour cells invasion and migration, promoting tumour metastasis.19 P‐Stat3 regulates the progression of nasopharyngeal and breast cancer by activating Jab1.23, 24 JAK/Stat329 and Jab125 are implicated in the mechanisms of EMT in different types of human cancer. Here, COPS5 is linked to cancer.