Affiliations: School of Pharmaceutical Sciences, Universiti Sains
Malaysia, Penang, Malaysia | Department of Surgery, Penang General Hospital,
Penang, Malaysia
Note: [] Corresponding author: Dr. Lay-Harn Gam, School of
Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, Penang,
Malaysia. Tel.: +604 6533888 ext 2208; Fax: +604 6570017; E-mail: layharn@usm.my
Abstract: Breast cancer is a leading cause of mortality in women. In Malaysia,
it is the most common cancer to affect women. The most common form of breast
cancer is infiltrating ductal carcinoma (IDC). A proteomic approach was
undertaken to identify protein profile changes between cancerous and normal
breast tissues from 18 patients. Two protein extracts; aqueous soluble and
membrane associated protein extracts were studied. Thirty four differentially
expressed proteins were identified. The intensities of the proteins were used
as variables in PCA and reduced data of six principal components (PC) were
subjected to LDA in order to evaluate the potential of these proteins as
collective biomarkers for breast cancer. The protein intensities of SEC13-like
1 (isoform b) and calreticulin contributed the most to the first PC while the
protein intensities of fibrinogen beta chain precursor and ATP synthase D chain
contributed the most to the second PC. Transthyretin precursor and
apolipoprotein A-1 precursor contributed the most to the third PC. The results
of LDA indicated good classification of samples into normal and cancerous types
when the first 6 PCs were used as the variables. The percentage of correct
classification was 91.7% for the originally grouped tissue samples and 88.9% for cross-validated samples.
Keywords: Breast cancer, proteomics, biomarkers, PCA, LDA
