Interleukin (IL)-8 is one of several angiogenic factors produced in bladder cancer cell lines. Although many studies have indicated that IL-8 is increased in infectious/inflammatory processes, elevated levels of IL-8 in urine also may be indicative of active transitional cell carcinoma (TCC).

Urinary IL-8 levels were measured with an enzyme-linked immunosorbent assay in subjects with TCC (n = 51), prostate cancer (n = 17), or a history of successfully treated TCC (n = 23) and in healthy subjects (n = 49). In addition, urinary IL-8 levels were measured in 21 subjects before, during, and 1 month after intravesical therapy with bacille Calmette-Guérin or mitomycin C.

The median urinary IL-8 levels were greater in subjects with TCC (64 pg/mL urine) than in healthy subjects (6 pg/mL urine), subjects with prostate cancer (0.5 pg/mL urine), or subjects with a history of successfully treated TCC (5.0 pg/mL urine). Urinary IL-8 levels were greater in subjects with invasive (high-stage) TCC than in those with low-stage TCC. Furthermore, the postintravesical instillation levels of urinary IL-8 levels were greater in patients whose TCC recurred compared with those whose TCC was in remission.

IL-8 levels were greater in subjects with TCC compared with those with successfully treated TCC. IL-8 levels increased with TCC stage, indicating that they are greater in more invasive (ie, angiogenic) tumors. A reduction in urinary IL-8 levels after treatment with bacille Calmette-Guérin or mitomycin C may reflect a decrease in bladder cancer cells and/or in other cells that produce IL-8.