MICROSATELLITE ALTERATIONS IN SERUM DNA OF HEAD AND NECK-CANCER PATIENTS

Microsatellite DNA alterations are an integral part of neoplastic prog ression and are valuable as clonal markers for the detection of human cancers(1-3). Moreover, recent evidence suggests that senescent tumor cells may release DNA into the circulation, which is subsequently carr ied by and therefore enriched in the serum and plasma(4,5). We tested 21 patients with primary head and neck squamous cell carcinoma (HNSCC) by polymerase chain reaction (PCR)-based microsatellite analysis of D NA from lymphocytes and paired serum samples. Patients were scored for alterations as defined by the presence of new alleles (shifts) or los s of heterozygosity (LOH) in serum at each of 12 markers and then comp ared with primary tumor DNA. Six out of 21 patients (29%) were found t o have one or more microsatellite alterations in serum precisely match ing those in the primary tumors. All six patients had advanced disease (stage III or IV); five of these patients had nodal metastases, three later developed distant metastases, and four died of disease. Microsa tellite analysis of serum represents a novel method for the detection of circulating tumor cell DNA. If these results are confirmed in large r studies, microsatellite markers may be useful in assessing tumor bur den in cancer patients.