Purpose: There is increasing interest in circulating tumor cells (CTCs) as a biomarker in bladder cancer (BC). In the present pilot study, we used a platform originally developed for detection of breast cancer CTCs to assess breast cancer-associated transcripts in CTCs of patients with different stages of BC. Moreover, transcripts specific for cancer stem cells and epithelial mesenchymal transition (EMT) were assessed.
Methods: We prospectively enrolled 83 BC patients and 29 controls. The AdnaTest® system was used to enrich epithelial cells in peripheral blood and to detect breast cancer-associated, stem cell-specific or EMT-specific transcripts. Test results were correlated with clinical and pathological stage.
Results: A positive AdnaTest® BreastCancerDetect was present in 6.9 % of controls (group A), 6.7, 15.0 and 18.7 % of patients with non-muscle-invasive BC (B), cM0 muscle-invasive BC (C) and metastatic BC (D) (p = 0.13). Stem cell-specific transcripts in group A, B, C and D were detected in 10.3, 10.0, 22.5 and 31.3 % (p = 0.03). EMT-associated transcripts were present in 3.5, 3.3, 15.0 and 18.7 % (p = 0.03). In group C, epithelial and stem-like transcripts correlated with tumor stage (p = 0.01 and 0.04).
Conclusions: CTCs with expression of breast cancer-associated transcripts are present in a considerable proportion of patients with BC. EMT and stem cell-specific transcripts of CTCs correlate with clinical stage and can be detected in patients negative for epithelial transcripts. The prognostic relevance of AdnaTest® results in BC patients and potential implications for therapy decisions remain to be determined in prospective studies.
Keywords: AdnaTest; Biomarker; Bladder cancer; Circulating tumor cells.