Extracellular matrix (ECM)
proteins, such as
collagen type I and
elastin, and intermediate filament (IMF)
proteins, such as
vimentin are modified and dysregulated as part of the malignant changes leading to disruption of tissue homeostasis. Noninvasive
biomarkers that reflect such changes may have a great potential for
cancer. Levels of
matrix metalloproteinase (
MMP) generated fragments of
type I collagen (C1M), of
elastin (ELM), and of citrullinated
vimentin (VICM) were measured in serum from patients with
lung cancer (n = 40),
gastrointestinal cancer (n = 25),
prostate cancer (n = 14),
malignant melanoma (n = 7),
chronic obstructive pulmonary disease (
COPD) (n = 13), and
idiopathic pulmonary fibrosis (IPF) (n = 10), as well as in age-matched controls (n = 33). The area under the receiver operating characteristics (AUROC) was calculated and a diagnostic decision tree generated from specific cutoff values. C1M and VICM were significantly elevated in
lung cancer patients as compared with healthy controls (AUROC = 0.98, P < 0.0001) and other
cancers (AUROC = 0.83 P < 0.0001). A trend was detected when comparing
lung cancer with COPD+IPF. No difference could be seen for ELM. Interestingly, C1M and VICM were able to identify patients with
lung cancer with a positive predictive value of 0.9 and an odds ratio of 40 (95% CI = 8.7-186, P < 0.0001).
Biomarkers specifically reflecting degradation of
collagen type I and citrullinated
vimentin are applicable for
lung cancer patients. Our data indicate that
biomarkers reflecting ECM and IMF
protein dysregulation are highly applicable in the
lung cancer setting. We speculate that these markers may aid in diagnosing and characterizing patients with
lung cancer.