Plasma YKL-40 is elevated, defined as higher than the age-adjusted 95th percentile of plasma YKL-40 in healthy subjects, in some patients with primary or advanced adenocarcinoma of the breast [33,48,49,50,51], colorectal [52,53,54], endometrial [55], lung [56], pancreas [28,29,57], prostate [58,59,60], ovary [36,61,62,63,64,65] and cervix [66]. This evidence concerns the gene CHI3L1 and breast adenocarcinoma.