XXXX mutation is a key molecular feature of pediatric @entity150 . A detailed report of three cases.

@entity1 @entity4929 @entity22563 @entity2557 @entity5 @entity470 @entity189 @entity876 @entity150 @entity10412 @entity983 @entity8498 @entity1722 @entity995
INTRODUCTION: @entity189 ( @entity189 ) of the bladder is a rare entity in the pediatric population, with an incidence of less than 0.4% in @entity1 younger than 20 years. These @entity1 overwhelmingly present with non-muscle-invasive low-grade disease and an indolent behavior. OBJECTIVE: The aim was to determine the source of the different natural history between pediatric population and adults; we hypothesized that pediatric @entity150 may stem from different molecular pathways. Our objective with this descriptive case series was to study the main genes involved in pediatric @entity150 using immunohistochemical (IHC) and mutational analysis. By studying the genetic alterations and immunophenotype of the most commonly altered genes in bladder @entity5 in three @entity5 we could gain better understanding of the molecular pathogenesis in this rare disease. STUDY DESIGN: Formalin-fixed paraffin-embedded (FFPE) tissue slides of urothelial @entity150 from three pediatric @entity1 were retrospectively identified at Columbia University pathology archives (1990-2011) and re-evaluated. @entity2557 , @entity8498 , and @entity10412 hotspots mutational analyses were conducted by polymerase chain reaction amplification and Sanger sequencing from the FFPE tissue blocks. IHC analysis was conducted using antibodies against @entity876 , @entity983 , @entity995 , @entity470 , and @entity1722 . Proliferative rate was assessed by Ki-67 expression. RESULTS: Two @entity1 had low-grade Ta disease, whereas the other @entity5 was classified as a @entity4929 of low malignant potential. None of the lesions recurred. Notably, all specimens showed @entity8498 @entity22563 mutation, whereas they were characterized by wild-type @entity2557 and @entity10412 . Nuclear @entity876 was not detected, whereas @entity983 and @entity995 expression were maintained. @entity470 was expressed in the three cases and @entity1722 was negative. The proliferation rate was very low in all cases. DISCUSSION: It is difficult to draw strong conclusions from the study of three @entity5 treated at the same institution and from the same referral population, and a multicentric study should be performed to confirm these preliminary results. However, we propose that @entity8498 mutation analysis could be performed on urothelial @entity150 of pediatric @entity1 . The knowledge in the molecular basis of urothelial @entity150 in @entity1 opens a promising field which could lead us to establish different guidelines for surveillance and follow-up of pediatric @entity150 @entity1 . CONCLUSION: @entity5 are characterized by a consistent @entity8498 mutation status, whereas @entity2557 and @entity876 pathways are not involved in this @entity5 initiation. These results may explain the few recurrences seen in this population.
