Prospecção de candidatos a biomarcadores oncológicos de cânceres gástricos por espectrometria de massas

Abstract

ancer is a disease in expansion, whose mortality is one of the highest in the world, motivating the scientific community to increasingly seek early diagnosis, as the chances of cure are higher in this case. Gastric cancer is of particular interest as it is the fourth most common in malignancy and the second leading cause of death worldwide. In this work, we compared tissue samples from control subjects (without the disease) and patients with gastric cancer and their corresponding ressection margin by using proteomics, metabolomics, and molecular biology. The proteomic analysis comprised an offline MudPIT shotgun proteomic approach with label-free quantitation by extracted ion chromatograms (XICs); it revealed that each of these tissue-types is very distinct. The resection margin presented several proteins previously correlated with cancer, but also several other proteins that could be related to tumor nourishment and metastasis. Some examples are: collagen alpha-1, ceruloplasmin, calpastatin, and E-cadherin. The multivariate analysis, according to Ward’s method and k-means clustering, of our metabolomics data revealed that was able to group the different samples according to their tissue type. Our metabolomic analysis results are aligned with those from the proteomics in that these tissue-types are very distinct, particularly the ressection margin which may be the result of an ongoing biochemical battle between the body and the cancer cells. Furthermore, a viral investigation of the samples by PCR (Polymerase Chain Reaction) showed that the Epstein-Barr virus (EBV) should be considered as a risk factor for gastric cancer in Manaus. In all, the proteomic results poses the ressection margin as playing a key role in the nutrition of the cancer cells. Regardless, we still need a better understanding of this disease at the molecular level to provide more effective treatments.