['Soluble c-erbB-2 oncoprotein has been proven as a useful marker in the management of breast cancer patients, but its value in diagnostics and follow-up of colorectal cancer patients remains controversial. The aim of this study was to evaluate the usefulness of serum c-erbB-2 monitoring in diagnostics and prediction of disease outcome in rectal cancer patients.', 'Serum samples from 88 patients with rectal adenocarcinoma before surgery and from 41 healthy controls were tested for the presence of c-erbB-2 oncoprotein by ELISA, and the patients were followed up for at least 5 years after the surgery.', 'Preoperative serum c-erbB-2 levels were significantly higher in stage IV patients than in healthy controls (P<0.001) and did not show correlation with preoperative CEA levels. Elevated preoperative serum c-erbB-2 levels showed relatively high specificity (88%) and low sensitivity (44%) in the diagnosis of rectal cancer. Elevated preoperative oncoprotein levels were predictive neither for overall survival nor for development of local recurrence/distant metastases.'] Do preoperative serum levels of c-erbB-2 seem to be useful in management of patients with rectal cancer?