The present invention provides methods and compositions for screening, diagnosis and prognosis of colorectal cancer, kidney cancer, liver cancer, lung cancer, lymphoid leukaemia (particularly chronic lymphocytic leukaemia), ovarian cancer or pancreatic cancer, for monitoring the effectiveness of colorectal cancer, kidney cancer, liver cancer, lung cancer, lymphoid leukaemia (particularly chronic lymphocytic leukaemia), ovarian cancer or pancreatic cancer treatment, and for drug development.