SDC1 and lung carcinoma: HBV is a small single-strand circular DNA virus that may be able to attach to heparan sulfate (HS) molecules and cell-free HS or SDC1, a transmembrane (type I) HS proteoglycan (HSPG), which occurs within clusters of integrins of the extracellular matrix (ECM) (Shi et al., 2013), which are receptors encoded by a common DEG in lung cancer (Supplementary Table 1).