Mass spectrometry-based serum peptidomic patterns for cervical cancer detection

Abstract

Cervical cancer is the common malignancy among females worldwide, especially in developing country. Due to high mortality and lack of sensitivity and specificity of the screening tests (Pap smear and HPV DNA test), an alternative tool is crucially needed. Interestingly, the peptide pattern is an alternative diagnostic tool for discriminating healthy women from cervical cancer patients. The serum peptide profiles from healthy subjects and cervical cancer patients were acquired using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 222 serum samples (83 healthy women and 139 cervical cancer patients) were divided into 2 independent datasets: training set (30 healthy women and 75 cervical cancer patients) and validation set (53 healthy subjects and 64 cervical cancer patients). Each specimen was pooled together according to each sample group [patients with cervical cancer (precancerous, stage I, II and III) and healthy women]. Prior to mass spectrometry analysis, serum peptides were prepared by ZiptipC18. Finally, the results were analyzed using FlexAnalysis 3.0, ClinProTools 2.2 and BioTyper 2.0 software. The serum peptide profiles in the range 1000 and 10000 Da were analyzed and shown as the chromatogram, gel view and dimensional image of principal component analysis (PCA). Based on peptide mass fingerprint (PMF), we were able to discriminate and category healthy subjects and patients with stage of cancer: precancerous, stage I, II and III. Furthermore, all PMF from pooled stage serum were used as reference mass spectrum in the in-house database and were used to classify samples. Compare to the clinical diagnosis, MALDI-TOF MS yields a sensitivity (60.97%) and high specificity (93.69%). Furthermore, the peak at 1466.91 Da was significantly differenced among the investigated groups (Wilcoxon/Kruskal-Wallis test (pWk), p<0.001), it is, therefore, an interesting molecule for the further study. The results of this study conclude that MALDI-TOF MS method might be used as an alternative approach for cervical cancer test with good repeatable, high accuracy, and less time-consuming.