Can bladder adenocarcinomas be distinguished from schistosomiasis-associated bladder cancers by using array comparative genomic hybridization analysis?

Bladder cancer is the most common malignancy in many tropical and subtropical areas, correlating well with the endemicity of schistostomiasis. The majority of schistostomiasis-associated (SA) bladder cancers are squamous cell cancers, whereas the majority of non-SA cases in the Western world are transitional cell cancers, suggesting different carcinogenetic mechanisms. Approximately 6% of SA and 1% of non-SA cases are adenocarcinomas. To achieve fine-resolution information of DNA copy number changes in SA adenocarcinomas, 10 tumor samples were analyzed on an oligonucleotide-based CGH array. The frequency of aberrations ranged from 2 to 17, with an average of 10 alterations per sample. The most frequently gained regions were 20q and 8q (in 70 and 60% of the cases, respectively), whereas the most frequently lost regions were 5q and 8p (both in 40% of the cases). In addition, six regions of amplification were found in three samples, containing both well characterized and novel regions. Comparison of the DNA copy number profiles to previously reported profiles of SA transitional cell carcinoma and squamous cell carcinoma revealed similarities (e.g., gains at 5p and 8q), as well as differences (e.g., TCC- and SCC-associated losses at 18p and 20p, and adenocarcinoma-associated gains at 20q). The results suggest that although SA cancers share genetic features, there also exist histology-specific regions of gain and loss.