The imprinted H19 gene is a marker of early recurrence in human bladder carcinoma

Abstract

Aims: To investigate the expression of the imprinted oncofetal H19 gene in human bladder carcinoma and to examine the possibility of using it as a tumour marker, similar to other oncofetal gene products.

Methods: In situ hybridisation for H19 RNA was performed on 61 first biopsies of bladder carcinoma from Hadassah Medical Centre in Jerusalem. The intensity of the reaction and the number of tumour cells expressing H19 in each biopsy were evaluated in 56 patients, excluding biopsies with carcinoma in situ. The medical files were searched for demographic data and disease free survival.

Results: More than 5% of cells expressed H19 in 47 of the 56 (84%) biopsies. There was a decrease in the number of cells expressing H19 with increasing tumour grade (loss of differentiation) (p = 0.03). Disease free survival from the first biopsy to first recurrence was significantly shorter in patients with tumours having a larger fraction of H19 expressing cells, controlling for tumour grade. This was also supported by the selective analysis of tumour recurrence in patients with grade I tumours.

Conclusions: It might be possible to use H19 as a prognostic tumour marker for the early recurrence of bladder cancer. In addition, for the gene therapy of bladder carcinoma that is based on the transcriptional regulatory sequences of H19, the expression of H19 in an individual biopsy could be considered a predictive tumour marker for selecting those patients who would benefit from this form of treatment.

Figure 1

H19 expression in bladder carcinoma as demonstrated by in situ hybridisation, using digoxigenin labelled antisense probes of H19, with Giemsa as a counterstain. In this microscopic field more than two thirds of the tumour cells express H19 (+++).

Figure 2

The mean fraction of tumour cells expressing H19 (defined as “quantity of H19”) calculated for tumour grade (WHO classification) in 56 patients. The “quantity” was defined as follows: only a few cells (< 5%), ± (0.5); up to one third of the cells, + (1); one to two thirds, ++ (2); more than two thirds, +++ (3). There was a significant decrease in the quantity of H19 with increasing tumour grade (Kruskal-Wallis one way ANOVA, p = 0.03).

Figure 3

The mean fraction of tumour cells expressing H19 (defined as “quantity of H19”) calculated for tumour stage, non-invasive (0) or invasive (> 0), of 56 patients. There was a significant decrease of quantity of H19 in invasive tumours (Mann-Whitney test, p = 0.03).

Figure 4

Disease free survival in months of 48 patients with no evidence of residual disease calculated for “quantity of H19” as defined above (see fig 2 ▶). The disease free survival was shorter for the quantity of H19 defined as 3 (log rank test, p = 0.05; Breslow test, p = 0.04).