Method for the in vitro diagnosis of a predisposition to bladder cancer or of the occurrence of bladder cancer and a kit for performing said diagnostic method

A method for the in vitro diagnosis of a predisposition to bladder cancer or of the occurrence of a bladder cancer in a human patient, wherein said method comprises the steps of:

• a) performing an allelotyping analysis respectively (i) of the blood DNA and (ii) of the urine DNA from said patient, using a serial of microsatellite markers associated with bladder cancer,
• b) determining the allele ratio for each microsatellite marker respectively (i) (Bb/Ba) for the blood DNA and (ii) (Ub/Ua) for the urine DNA, wherein:
• Ba and Bb represent the respective frequency of the two alleles of said microsatellite marker in the blood DNA of said patient, and
• Ua and Ub represent the respective frequency of the two alleles of said microsatellite marker in the urine DNA of said patient,
• c) determining, for each microsatellite marker, the absolute value of the percentage of Allelic Imbalance (AI%) between the allele ratios (Bb/Ba) and (Ub/Ua) determined at step b), according to the following formula:
• AI%=((Bb/Ba)−(Ub/Ua))×100/(Bb/Ba),
• and
• d) comparing, for each microsatellite marker, the AI% value found for said patient with a control AI% value for the same marker found in individuals who are not predisposed nor affected with bladder cancer and wherein a difference between the patient AI% value and the control AI% value of more than a predetermined cut-off value, for at least one microsatellite marker, is indicative of a predisposition to, or of the occurrence of, a bladder cancer in said patient.