PDCD1 and alveolar soft part sarcoma: Plasma samples from alveolar soft part sarcoma (ASPS), NSCLC or lymphoma patients prior to anti-PD1 therapy were screened using a protein array platform called Nucleic Acid Programmable Protein Array (NAPPA), which has been widely applied in the identification of AAb biomarkers for cancers and autoimmune diseases 21.