Additional analysis revealed higher expression of YKL40 in patients with biochemically recurrent (three consecutive increases in the serum level of PSA after radical prostatectomy) PCa disease when compared with those with non-recurrent disease (Fig. 3E, GDS4109; Sun & Goodison 2009), which also corroborates the trends observed at the protein level in a previous study (Johansen et al. 2007). This evidence concerns the gene CHI3L1 and posterior cortical atrophy.