SOLUBLE CD44 ISOFORMS IN SERUM AS POTENTIAL MARKERS OF METASTATIC GASTRIC-CARCINOMA

A splice variant of CD44 (exon V4-V7) confers metastatic behavior in a rat carcinoma model; aberrant expression of splice variants has been detected on a variety of human tumor cell lines as well as primary and metastatic human tumors, including lymphomas, carcinomas (colon, thyr oid, mamma, bladder), and glioma. We used enzyme-linked immunosorbent assay to determine the concentration of soluble CD44 in the serum samp les of 10 normal individuals and 41 patients with various stages of ga stric cancer. Soluble CD44S and its isoforms, V5 and V6, were present in the serum of normal individuals (288.53 +/- 18.33, 25.49 +/- 1.70, and 148.32 +/- 3.15 ng/ml, respectively). The concentrations of solubl e CD44 V5 and V6 were elevated in patients with advanced gastric carci noma (69.39 +/- 6.06 and 216.62 +/- 32.98 ng/ml, respectively). Serum CD44 V5 concentrations correlated with the extent of tumor invasion (T ), the status of lymph node involvement (N), and distant metastasis (M ) (TNM staging) (p < 0.05), whereas CD44S did not. These results sugge st that detection of abnormal regulation of CD44 splicing could be hel pful in gastric cancer diagnosis and disease evaluation.