Background: To determine whether MUC7 gene expression can be used as a bladder cancer marker in peripheral blood.
Methods: Nested reverse transcription-polymerase chain reaction (RT-PCR) was performed on four types of bladder cancer cell lines (RT4, T24, EJ-1 and TCC) and the peripheral blood of 38 (31 superficial disease and seven invasive disease) bladder cancer patients and 18 subjects with urinary tract infections or other non-malignant conditions to determine the expression of MUC7.
Results: No MUC7 gene expression was detected in control subjects. MUC7-positive cells were detected in all bladder cancer cell lines and in 18 of 38 (47.4%) peripheral blood samples of bladder cancer patients. Based on the tumor stage, MUC7 was detected in 11 of 29 (37.9%) patients with superficial disease (Ta and T1) and in seven of nine (77.7%) invasive disease patients (>/=T2). There was a significant difference between superficial and invasive disease (P = 0.042). Based on tumor grade, we could not detect MUC7 in five patients with grade 1, in five of 15 patients (33.3%) with grade 2 and in 13 of 18 patients (72.2%) with grade 3. There was a significant difference between grades 1 and 3 (P = 0.007) and grades 2 and 3 (P = 0.025).
Conclusions: These results suggest that MUC7 is a highly specific marker for bladder cancer and may be a useful method for the molecular staging and management of bladder cancer.