To assess whether immunostaining for deleted-in-colon-cancer (DCC) protein, a previously established prognostic marker in colon and bladder cancer, may assist in resolving the uncommon differential diagnostic dilemma of distinguishing primary from secondary urothelial adenocarcinoma.

The study group consisted of 12 patients with adenocarcinoma involving the bladder or ureter and previously resected colorectal carcinoma between 1988 and 2002. All patients were initially considered to have primary urothelial transitional cell carcinoma, and the management strategy was conducted accordingly. The clinical data were recorded from the charts, and immunohistochemical staining for DCC was performed on formalin-fixed paraffin-embedded tissues containing the primary colorectal cancer and ensuing urinary tract tumor. Staining was defined as positive when at least 25% of the tumor cells were immunoreactive for DCC.

Of the 12 patients, 10 presented with bladder and 2 with ureteral adenocarcinoma. All secondary tumors originated from a primary carcinoma invariably located along the left colon or rectum. The overall 5-year disease-specific survival rate from the time of colectomy was 31% at a median follow-up of 50 ± 8 months. Of the 12 patients, 5 (41%) had positive DCC immunoreactivity. In all cases, concordant expression of DCC was found in the primary colorectal cancer and the ensuing tumor in the urinary tract. The survival time from colectomy was significantly longer for the DCC-positive subgroup (median 59 months, 95% confidence interval 41 to 77) than in the DCC-negative subgroup (median 23 months, 95% confidence interval 13 to 37). Likewise, the time lag between colectomy and tumor recurrence in the urinary tract was significantly longer in the patients with DCC-positive tumors (median 35 months) than in those with DCC-negative tumors (median 10 months).

DCC immunoreactivity was consistently observed in secondary bladder or ureteral adenocarcinoma when the primary colorectal lesion expresses DCC, and thus may serve to establish the origin of the tumor. Positive DCC protein expression in secondary urinary tract adenocarcinoma of colorectal origin may identify a subset of patients with a relatively favorable prognosis. Additional studies are required to confirm our results.