Rogan et al. found that P. aeruginosa-colonized CF cells had approximately threefold higher cathepsin expression than P. aeruginosa-negative cells and hypothesized that the antimicrobial glycoprotein lactoferrin was cleaved rapidly by cathepsins in the disease state of CF to prevent Pseudomonal biofilm formation [38]. This evidence concerns the gene CTSS and cystic fibrosis.