Abstract
There are urgent needs to develop methods for early detection of nonsmall cell lung cancer (NSCLC) because of its increasing incidence and poor prognosis. Here, we analyzed the production of IgG antibody (WT1 Ab) against WT1 (Wilms' tumor gene) protein that was overexpressed in the majority of NSCLC. Enzymeโlinked immunoโsorbent assay showed that WT1 Ab was produced in all of 91 NSCLC patients and 70 healthy individuals and that WT1 Ab titers were significantly higher in NSCLC patients compared with healthy individuals. When the cutโoff level of WT1 Ab titers were fixed at mean + 3SD of those in healthy individuals, 26.4% of NSCLC patients had WT1 Ab titers over the cutโoff level, and positive rates of WT1 Ab at each clinical stage were 25.0, 30.8 and 38.4% in stage I, II and III NSCLC, respectively. When WT1 Ab was combined with CEA or CYFRA for detection of NSCLC, positive detection rates increased from 25.0 to 34.1 and 31.8%, respectively, in stage I and from 38.4 to 69.2 and 46.1%, respectively, in stage III, but not changed in stage II. Western blot analysis showed that dominant subclass of WT1 Ab was Th1โtype IgG2. Interestingly, elevation of WT1 Ab titers was significantly associated with longer diseaseโfree survival in patients with stages IโIII NSCLC. These results showed that WT1 Ab could be a useful marker for early detection of NSCLC and its prognostic prediction. These results also suggested that WT1โspecific immune responses played an important role in antiโcancer immunity in NSCLC. ยฉ 2009 UICC