H19 and urinary bladder cancer: Although the IGF-2 is the first autosomal gene identified to exhibit imprinting, a study indicated that 2/9 (22.2%) of cases displaying loss of imprinting (LOI) of the IGF-2 and 2/16 (12.5%) had LOI of H19 in bladder cancer[25], However, the precise regulatory mechanism of the IGF-2 in transitional cell carcinoma is not clear.