Transcripts of circulating tumor cells detected by a breast cancer-specific platform correlate with clinical stage in bladder cancer patients

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. We prospectively enrolled 83 BC patients and 29 controls. The AdnaTest(A (R)) 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. A positive AdnaTest(A (R)) 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). 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(A (R)) results in BC patients and potential implications for therapy decisions remain to be determined in prospective studies.