Enrichment of Cancer Stem Cells in Urothelial Carcinoma and Small Cell Carcinoma of the Urinary Bladder.
Qiusheng Si, Li Xiao, Yolanta Bondaruk, Yan Wang, Bogdan Czerniak, Charles C Guo. University of Texas MD Anderson Cancer Center, Houston
Background: Recent studies have shown that most human cancers originate from a few cancer-initiating cells or cancer stem cells (CSCs). To understand the role of CSCs in bladder cancer, we determined the expression of aldehyde dehydrogenase 1 (ALDH1), a CSC marker, in urothelial carcinoma (UC) and small cell carcinoma (SmCC) of the urinary bladder.
Design: Tissue microarray blocks were constructed using urinary bladder specimens, which included UC (n=143), SmCC (n=19), and normal urothelium (n=11) tissue. Three 1.0-mm tissue cores were obtained from each case. Four-mm tissue microarray slides were used for immunohistochemical staining with ALDH1 (BD Transduction Laboratories, San Jose, CA). Cases were considered positive if more than 5% of analyzed cells showed robust immunostaining signaling for ALDH1 in the cytoplasm.
Results: The mean UC patient age was 66 years (range, 27-85 years). UC tumors were noninvasive in 90 cases, invasive in 53, high grade in 109, and low grade in 34. The mean SmCC patient age was 68 years (range, 34-90 years). No normal urothelial cells (0 of 11) showed immunoreactivity for ALDH1 on immunostaining, but 17% of UC samples (24 of 143) were positive. ALDH1 immunoreactivity was significantly higher in invasive UC (38%) than in noninvasive UC (4.7%) (p<0.05), but there was no significant difference between high- and low-grade UC. In addition, 55% of SmCC samples (10 of 19) were positive for ALDH1, which was significantly higher than in invasive UC (p<0.05).
Conclusions: Our results suggest that CSCs are present in UC of the urinary bladder. CSCs are more commonly present in invasive UC than in noninvasive UC, suggesting that they play an important role in UC progression. The enrichment of CSCs in SmCC raises the possibility that SmCC may have a close association with CSCs.
Category: Genitourinary (including renal tumors)
Tuesday, March 1, 2011 9:30 AM
Poster Session III # 187, Tuesday Morning