PTK2 and pulmonary fibrosis: Using the quantifiable measure of hydroxyproline as a surrogate for the total collagen content in whole lung tissues, FAK inhibitor significantly decreased total collagen level in bleomycin-challenged mice when compared to that in vehicle treated mice (Fig. 4C, about a 1.1-fold decrease, or 256 μg to 123 μg decrease per lung, p < 0.01), demonstrating the FAK inhibitor significantly reduced lung fibrosis.