Integrated Plasma and Tumor Proteomics of Nasopharyngeal Carcinoma in a Moroccan Cohort

Nasopharyngeal carcinoma (NPC) is a multifactorial disease mainly affecting the Southeast Asian and North African populations. Critically, there is a dearth of available circulating biomarkers for NPC. Additionally, as of this writing, there have been no prior plasma proteomics studies on NPC in the Moroccan population. Accordingly, there has been no integrated analysis of tumor and plasma for NPC in the Moroccan sub-population. Label-free proteomics analysis was conducted on 25 samples of Moroccan origin (10 NPC samples and 15 healthy control samples). Each sample was depleted of albumin, fractionated into eight fractions, and then analyzed using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). A total of 291 proteins and 2702 unique peptides were identified across all samples. In total, 16 proteins were differentially expressed (DEPs) between NPC cases and healthy individuals. Of these, three showed prognostic significance, while four demonstrated diagnostic potential. A pathway analysis showed significantly enriched terms related to the immune response and chronic inflammation, revealing acute-phase proteins as differentially expressed. The investigation of patients with early and advanced stages of NPC revealed two DEPs, while four additional DEPs were identified across the three defined clusters of NPC. Across all comparisons, DEPs, such as H2A, IGHG2, SERPINA3, SAA1, CRP, PIGR, and APOA2, have shown potential as biomarkers for NPC, with several being identified for the first time. We additionally compared the plasma proteomic profile of NPC with the tumor proteomic profile, highlighting that deeper proteomics analysis of plasma may be required to quantify additional putative biomarkers that may be shed from the tumor into the blood. Our research presents the first plasma proteomic profile of NPC in Morocco and North Africa, identifying proteins that might ultimately have diagnostic and prognostic potential.