Serum levels of CA15-3, KL-6 and BCA225 are positively correlated with each other in the general population.

BACKGROUND Carbohydrate antigen 15-3 (CA15-3), Kerbs von den Lungen (KL-6) and breast cancer antigen 225 (BCA225) are widely used tumor markers for breast and lung cancer respectively. PATIENTS AND METHODS We analyzed 460 Japanese volunteers for 99 items on blood examination including 27 serum tumor markers. Correlations between 27 tumor markers and the other items were statistically analyzed. RESULTS Positive correlations were identified between CA15-3 vs. KL-6, CA15-3 vs. BCA225, and KL-6 vs. BCA225, with correlation coefficients of 0.84, 0.86, and 0.79, respectively. CONCLUSION This is the first report to show a positive correlation among these markers in the general population. All of these are recognized as belonging to the mucin family, and this might be the reason for the positive correlation.