Chromosomal aberrations in Cis and Ta bilharzial bladder cancer: a theory of pathogenesis

Bladder cancer manifests many different forms ranging from superficial to aggressive muscle invasive stages, which suggests that various genetic alterations are involved. Several attempts have been made to establish correlations between specific genetic alterations and various stages of the disease. At the National Cancer Institute (NCI), Cairo, bladder cancer constitutes 30.3% of all cancers. Bladder cancer observed among Egyptians has a clinico-pathological profile that differs from transitional cell carcinoma (TCC) seen in the western world.

We used fluorescence in situ hybridization to detect numerical chromosome changes in 25 patients presenting with carcinoma in situ and Ta lesions. Twenty-four cases had transitional cell carcinoma and one case had squamous cell carcinoma.

Five out of 24 TCC cases had diploid chromosome count with all the probes. Numerical chromosome aberrations were detected in 19 cases (79%). In eight cases, a loss of chromosome 9 was observed. In one case, an additional loss of chromosome 17 was detected. One case demonstrated a loss of chromosome 17, whereas another three cases showed a gain of chromosome 7. Loss of chromosome Y was observed in nine of the 22 male cases studied (40.9%). The only case with SCC had normal diploid chromosome count with all the probes used.

When the genetic basis of bilharzial related bladder cancer is fully understood, new diagnostic and therapeutic strategies will be developed, which in turn may promote better clinical management by pathologists and urologists. A theory of bilharzial related bladder cancer pathogenesis is suggested.