Inactivation of the "deleted in colon cancer" (DCC) gene on chromosome 18 is known to be associated with the tumorigenesis and metastasis of colorectal cancer. In the present study, we investigated the expression of DCC and the c-erbB-2 product in surgical specimens from 45 patients with breast cancer by immunohistochemical staining, and found the expression of DCC to be decreased in 23 (51%) tumors. In 8 years of follow-up, 11 of 22 (50%) patients with DCC-positive staining tumors, and 17 of 23 (74%) patients with DCC-negative tumors developed recurrence. The stratified analysis, according to the status of axillary lymph node metastasis, showed the same tendency. Overexpression of erbB-2 was detected in 13 (29%) of the 45 breast cancer specimens, but there were no differences in the relapse rate between patients with erbB-2 positive and those with erbB-2 negative tumors. Although the individual alteration of DCC or erbB-2 did not possess independent prognostic significance for the prediction of recurrence, patients with tumors having the double alteration of DCC-negative and erbB-2-positive showed adverse relapse-free survival (0.025 < P < 0.05). These findings suggest that a decrease in DCC expression and erbB-2 overexpression may influence the progression of breast carcinoma.