Abstract
BACKGROUND: Biomarkers that predict which patients with early stage NSCLC will develop recurrent disease would be of clinical value. We previously discovered that an autoantibody to a complement regulatory protein, complement factor H (CFH), is associated with early stage, non-recurrent NSCLC, and hypothesized that the anti-CFH antibody inhibits metastasis. OBJECTIVES: The primary objective of this study was to evaluate the anti-CFH antibody as a prognostic marker for recurrence in stage I NSCLC. A secondary objective was to determine if changes in antibody serum level one year after resection were associated with recurrence. METHODS: Anti-CFH antibody was measured in the sera of 157 stage I NSCLC patients designated as a prognostic cohort: 61% whose cancers did not recur, and 39% whose cancers recurred following resection. Impact of anti-CFH antibody positivity on time to recurrence was assessed using a competing risk analysis. Anti-CFH antibody levels were measured before resection and one year after resection in an independent temporal cohort of 47 antibody-positive stage I NSCLC patients: 60% whose cancers did not recur and 40% whose cancers recurred following resection. The non-recurrent and recurrent groups were compared with respect to the one-year percent change in antibody level. RESULTS: In the prognostic cohort, the 60-month cumulative incidence of recurrence was 40% and 22% among antibody negative and positive patients, respectively; this difference was significant (Gray's test, P= 0.0425). In the temporal cohort, the antibody persisted in the serum at one year post-tumor resection. The change in antibody levels over the one year period was not statistically different between the non-recurrent and recurrent groups (Wilcoxon two-sample test, P= 0.4670). CONCLUSIONS: The anti-CFH autoantibody may be a useful prognostic marker signifying non-recurrence in early stage NSCLC patients. However, change in the level of this antibody in antibody-positive patients one year after resection had no association with recurrence.