CHI3L1 and neoplasm: When compared with doxycycline-untreated mice (6.2±3.7 ng/ml), the average CHI3L1 concentration was increased more than 5-fold (33.5±35.6 ng/ml, p<0.001) in doxycycline-treated mice without tumor (prior tumor formation), and was increased more than 26-fold (159.0±90.0 ng/ml, p<0.001) in doxycycline-treated mice with tumor (Figure 2, lower panel).