Recently, it has been shown that oncogene-induced senescence (OIS) occurs during the early stages of tumorigenesis. Senescent tumour cells are abundant within premalignant neoplastic lesions, whereas they are scarce in malignant tumours. This association of senescence with the premalignant stages of tumour progression opens the possibility of using senescence markers as diagnostic and prognostic tools. Moreover, some chemotherapeutic protocols induce senescence in tumour cells and, consequently, senescence markers could help to monitor treatment response.