Objectives: Genomic imprinting is a newly discovered mechanism in genetics that is involved in tumorigenesis. H19 is an imprinted gene in the human, expressed from the maternal allele. It is extensively transcribed in fetal life but is not translated and functions as an RNA molecule. It has been suggested as a candidate tumor suppressor gene. We studied the expression of H19 in human cancer arising from tissues expressing H19 in fetal life, one of which is bladder mucosa.
Methods: In situ hybridization for H19 mRNA on paraffin sections of bladder carcinoma in different histologic grades.
Results: Low-grade (grade 1 of 3), noninvasive (Ta) papillary transitional cell bladder carcinoma did not express H19, but prominent expression was disclosed in higher grades, invasive transitional cell carcinomas (T1-T3/4). Expression was also evident in in situ bladder carcinoma (Tis), which tends to progress rapidly to invasive cancer.
Conclusions: We suggest that H19 can be used as a tumor marker in human bladder carcinoma, where its expression indicates a more malignant potential.