These phenomena indicate that ROBO-FL-expressing tumour cells and SLIT2-expressing hepatocytes can coadapt and that loss of SLIT2 in the TME or blockade of ROBO1 can not only lead to failure of ROBO1+ tumour cells in the context of cell competition but can also lead to their elimination in the liver. The gene discussed is SLIT2; the disease is neoplasm.