Which molecular and genetic findings are characteristic of squamous cell carcinoma of the urinary bladder?

Updated: Jun 11, 2019
  • Author: Muhammad T Idrees, MD; Chief Editor: Liang Cheng, MD  more...
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Answer

The molecular data for squamous cell carcinoma of the bladder have emerged mostly from the analysis of schistosomal-associated cases. Overrepresentation of 5p, 6p, 7p, 8q, 11q, 17q, and 20q of chromosomal material has been detected by cytogenetic and classic molecular analysis. In addition, deletions at 3p, 4q, 5q, 8p, 13q, 17p, and 18q have also been reported. [45, 46, 47, 48, 49, 50, 51]

As with urothelial carcinoma, p53 positivity has been observed in schistosomal-associated squamous cell carcinoma in a wide range in different studies. [52, 53, 54, 55, 56] In one study, TP53 mutations in schistosomal-associated squamous cell carcinoma included more base transitions at CpG dinucleotides than seen in urothelial carcinomas. [54]

Other molecular alterations known to occur in urothelial carcinomas, such as HRAS mutations, [57, 58] epidermal growth factor receptor (EGFR) overexpression, and HER2 expression were also found at comparable frequencies in schistosomal-associated squamous cell carcinoma. [59] Methylation of DNA, as shown by detection of O6-methyldeoxyguanosine, has been found in a high percentage of patients with schistosomiasis-associated cancers in Egypt. [60, 61]

Few sporadic squamous cell carcinoma cases examined by classic cytogenetics and comparative genomic hybridization (GCH) have shown gains at 1q, 8qa, and 20q, as well as losses of 3p, 9p, and 13q. [46, 62, 63, 64]

In a more recent study, investigators indicate that TERT promoter mutation status appears to be able to help differentiate sites of small cell carcinoma of the urinary bladder from that of the prostate. [65]


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