Decreased nuclear localization of PRH has been observed in thyroid tumours and in subtypes of acute myeloid leukaemia and in both ductular and lobular IBCs.16, 17, 25 In liver cancer cells, PRH overexpression downregulates tumour growth in mouse xenograft models and PRH antagonizes c-Myc activity.13, 26 In well-differentiated liver tumours, there is little nuclear PRH expression and strong cytoplasmic expression, whereas in poorly differentiated tumours there is lower cytoplasmic expression of PRH. This evidence concerns the gene MYC and thyroid tumor.