As a part of the technical validation of the biomarker for the use of quantification of EL-NE, the antibody raised to capture this fragment was found in vitro to be capable of binding only the EL-NE fragment, with no binding of intact elastin, nor fragments of elastin degraded by MMP or cathepsin G [50] Consequently, this biomarker may be associated with the emphysema phenotype. Here, CTSG is linked to pulmonary emphysema.