These data suggest a favorable outcome regarding recurrence and progression in patients with superficial bladder cancer who undergo ReTURB. ReTURB is suggested at least in those at high risk when bladder preservation is intended.

In prostate carcinoma (PCa) increased DNA methylation ('hypermethylation') occurs at specific genes such as GSTP1. Nevertheless, overall methylation can be decreased ('hypomethylation') because methylation of repetitive sequences like LINE-1 retrotransposons is diminished. We analysed DNA from 113 PCa and 36 noncancerous prostate tissues for LINE-1 hypomethylation by a sensitive Southern technique and for hypermethylation at eight loci by methylation-specific PCR. Hypermethylation frequencies for GSTP1, RARB2, RASSF1A, and APC in carcinoma tissues were each 470%, strongly correlating with each other (Po10 À6 ). Hypermethylation at each locus was significantly different between tumour and normal tissues (10 À11 oPo10 3 ), although hypermethylation, particularly of RASSF1A, was also observed in noncarcinoma tissues. ASC1 hypermethylation was observed in a subgroup of PCa with concurrent hypermethylation. Hypermethylation of CDH1, CDKN2A, and SFRP1 was rare. LINE-1 hypomethylation was detected in 49% PCa, all with hypermethylation at several loci. It correlated significantly with tumour stage, while hypermethylation was neither related to tumour stage nor Gleason score. Coordinate hypermethylation of several genes may occur early in PCa, with additional hypermethylation events and LINE-1 hypomethylation associated with progression. Hypermethylation allows detection of 482% of PCas. PCa may fall into three classes, that is, with few DNA methylation changes, with frequent hypermethylation, or with additional LINE-1 hypomethylation.

Recent findings suggest an important role of the proto-oncogene c-kit, a surface membrane receptor of the tyrosine kinase family, and its ligand stem cell factor (SCF) in normal spermatogenesis and possibly in the pathogenesis of certain testicular germ cell tumors. To further investigate this potential role, the expression of c-kit and SCF was studied in normal and malignant human testicular tissue specimens at the mRNA and protein level by Northern blot analysis and immunohistochemistry, respectively. The detection of the c-kit receptor in normal human germ cells and its natural ligand SCF in Sertoli cells suggests the presence of a local trophic regulatory system that may be active in human spermatogenesis. Additionally, c-kit expression was detected in the seminoma but not in the nonseminoma subtype of human testicular germ cell tumors (GCT). Stem cell factor was not expressed at the mRNA level in tissue from either subtype of GCT as determined by Northern blot analysis; however, the protein was detected immunohistochemically in the cytoplasm of rare tumor cells.

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