Loss of heterozygosity in 8p and 11p as a prognostic marker for patients with transitional cell tumors of the urinary bladder
Purpose: Patients with TCT (transitional cell tumor) of the urinary bladder are prone to recurrence with risk of progression. Follow-up is done according to the tumor grade/stage, and there are to this date, no other significant prognostic markers. We wanted to investigate whether microsatellite analysis gives prognostic information on these patients during and after their tumor diagnosis and treatment.
Methods: Blood, urine and tissue samples of 59 patients with TCT (group A) and 25 patients with a history of TCT but no evidence of ongoing disease at the time of sample collection (group B), were analyzed. The first group of patients was followed-up for a median of 23.1 months (range: 2-48 months) and the second group for 25 months (range: 4-57 months). All samples were examined for LOH (loss of heterozygosity) on 13 microsatellites located on 10 different chromosomal arms. Finally, the correlation between LOH and recurrence, progression or mortality was investigated.
Results: Microsatellite analysis in tumor tissue of patients with non-invasive disease (24 out of 59 in group A) revealed that LOH in 11p correlated with recurrence (p= 0.044), while LOH in 8p correlated with progression (p= 0.033). Furthermore, the predictive value of LOH in 8p was also found in the urine sediment analysis (p= 0.005). In the patients with a history of TCT (group B), recurrence could be predicted by the combined analysis of 11p and 8p in the tissue (p=0.009).
Conclusions: Microsatellite analysis seems to have a significant prognostic value both for patients with non-invasive tumors as for patients with a history of TCT but no evidence of ongoing disease. The study of LOH could therefore aid to the sub-grouping of patients having tumors of the same grade/stage, into low- and high- risk groups, and to the consequential management of their follow-up.