Detection of APC and k-ras mutations in the serum of patients with colorectal cancer

Detection of tumor DNA in peripheral blood of patients with colorectal canc er (CRC) may allow early diagnosis of tumor disease and be of prognostic va lue. However, a reliable tumor marker detectable in the serum of patients w ith this disease is missing. Because k-ras and APC mutations occur frequent ly and at an early stage in CRCs, these mutations might also be detected in the serum of CRC patients and serve as tumor markers. Hence, tumor tissues of CRC patients were examined for the presence of mutations in the k-ras a nd APC genes. If a mutation was detected in the tumor, the serum of the pat ient was screened subsequently for the presence of this mutation. K-ras mut ations were detected in 22 of 30 colorectal tumor tissues, but only in six patients was the mutation identified in their serum samples. Mutations of t he APC gene were identified in 25 of 65 tumors; 20 of these 25 patients sho wed the respective mutation in their serum. Given their higher detection ra te, APC mutations could be a more informative serum marker than k-ras in CR C patients.