PCSK9 and neoplasm: This outcome was subsequently validated by IHC staining of GC tumor tissue.349 A separate proteomics-focused study echoed these findings, noting plasma PCSK9 concentrations to be 1.25-fold higher in the individuals with early-stage GC compared to those in good health.328 In a parallel vein, Xu and colleagues observed that serum PCSK9 concentrations in GC patients were notably higher than in their healthy counterparts.