DOI: 10.1177/0003702817723928 1 Raman Spectroscopy Combined with Principal Component Analysis for Screening Nasopharyngeal Cancer in Human Blood Sera Saranjam Khan 1* , Rahat Ullah 1 , Samina Javaid 2 , Shaheen Shahzad 2 , Hina Ali 1 , Muhammad Bilal 1,3 , Muhammad Saleem 1 , and Mushtaq Ahmed 1 1 Agri-biophotonics Laboratory, National Institute for Lasers &Optronics, Islamabad, Pakistan. 2 Department of Bioinformatics and Biotechnology , International Islamic University Islamabad, Pakistan. 3 Departmentof Physics and Applied Mathematics, Pakistan Institutes of Engineering and Applied Sciences, Islamabad, Pakistan. Corresponding Author: Dr. Saranjam Khan, Agri-Biophtonics Division, National Institute for Lasers and Optronics (NILOP), Islamabad, Pakistan. Email: k.saranjam@yahoo.com Abstract This study demonstrates the analysis of nasopharyngeal cancer (NPC) in human blood sera using Raman spectroscopy combined with the Multivariate analysis technique. Blood samples of confirmed NPC patients and healthy individuals have been used in this study. The Raman spectra from all these samples were recorded using 785 nm laser for excitation. Important Raman bands at 760, 800, 815, 834, 855, 1003, 1220–1275, and 1524 cm –1 , have been observed in both normal and NPC samples. A decrease in the lipids contents, phenylalanine, and β-carotene, whereas increases in amide III, tyrosine, and tryptophan have been observed in the NPC samples. The two datasets were well separated using principal component analysis (PCA) based on Raman spectral data. The spectral variations between the healthy and cancerous samples have been further highlighted by plotting loading vectors PC1 and PC2, which shows only those spectral regions where the differences are obvious. Keywords: Cancer, Raman spectroscopy, principal component analysis, PCA, nasopharynx, biomolecules