Early diagnosis of pancreatic cancer is an extremely challenging topic for the scientific community, and it is critical in clinical practice. When the PDAC patient accesses the clinical consultation, the disease is usually at an advanced stage, so much that surgery, to date still the most critical therapeutic option for PDAC treatment, is restricted to a small percentage of these patients. This highlights the importance of developing new technologies for the diagnosis of PDAC in its early stages where symptoms are mild and confoundable with those of other diseases [21]. Even though CA 19 − 9, the only clinical approved biomarkers for pancreatic cancer, is gaining importance to predict the advanced stages of PDAC [22], it is not recommended as an early predictor of this lethal malignancy. In the last five years, a significant contribution towards the development of new diagnostic tools has come from nanotechnology. It has been demonstrated that the protein corona that is absorbed on nanomaterials when they are exposed to patient plasma is personalized. This means that it varies from subject to subject and is influenced by the onset of cancer [16, 23–29] and other human conditions [30]. It is well known that cancer produces alterations in the human proteome from the earliest stages and these changes can significantly influence the composition of the protein corona. Having demonstrated that the protein corona is personalized paved the way for test development of the NEB test for the early diagnosis of PDAC [31, 32] and provided an impetus to serious work in this field. As an instance, we have shown that coupling the outcomes of the NEB test with the values of specific clinical parameters can boost the predictive capacity of the test itself [16]. The earlier versions of the NEB tests were based on the direct characterization of the protein corona, i.e., after the isolation of plasma proteins from the particle surface. However, several studies demonstrated that protein isolation from NPs is a crucial step that can affect the reproducibility of the data and decrease the sensitivity and specificity of the test [33]. Therefore, more recently we have explored the chance of distinguishing PDAC patients from healthy subjects by the indirect characterization of the protein corona, i.e., without the protein isolation step. Indirect methods of protein corona characterization look at the protein nanoparticle complex as a single entity. Among these approaches, MagLev has recently shown great promise for the classification of PDAC patients. In a typical test, nanoparticle-protein complexes are injected into a device filled with a liquid paramagnetic where they migrate in a high-intensity magnetic field. Depending on the experimental conditions, typical MagLev outputs such as the initial position in the test tube, the precipitation speed etc. can be identified as fingerprints for PDAC.
Taking advantage of these previous experiences, here we explored the ability of the MagLev technique in detecting PDAC when coupled with the blood levels of glucose, cholesterol and triglycerides. These parameters were chosen taking into account that the alteration in metabolic pathways, as the glycolytic and cholesterogenic ones, have an impact on the risk of development and differentiation of PDAC [5].
More in detail, as reported by Feng et al. hypertriglyceridemia represents a risk factor for the development of PDAC via bile acids metabolism. Moreover, highlighting how bile acids influence adipose tissue distribution, insulin sensitivity and triglyceride metabolism, the Authors reported how they are associated with risk factors of pancreatic cancer as hypertriglyceridemia, hyperglycemia [34]. As Chen et al. reported, hyperglycemia boosts the development of precancerous pancreatic lesions by triggering the Wnt/β-catenin signaling pathway [35]. Screening for PDAC in patients with hyperglycemia is both an old issue and a current challenge. Indeed, as highlighted by Pannala et al. [36], the fact that diabetes may improve after resection for pancreatic cancer also suggests that the increase in blood sugar is supported by the tumor. Moreover, the risk of developing PDAC is up to eight times higher in elderly subjects with new-onset diabetes. On the other hand, the widespread diffusion of primary type 2 diabetes in the general population [37], which is clinically indistinguishable from diabetes linked to cancer, complicates the matter. The above-mentioned earlier studies in the field of nanotechnology and the pieces of evidence supporting the link between PDAC and metabolic alterations prompted us to explore the combination of the technique's predictions with blood levels of glucose, cholesterol, and triglycerides.
Our results show that coupling the MagLev technology with the blood glycemic levels leads to high detection ability, while lower accuracy levels were obtained when the MagLev outcomes were coupled to blood levels of cholesterol and triglycerides.
Lastly, the fact that the analysis by gender has shown greater accuracy of the test in women is consistent with what has already been reported in the literature [4]. In presence of metabolic alterations, the risk to develop a pancreatic adenocarcinoma increases more for women. Moreover, while in men the strongest individual risk factors for global incident cancer are high levels of blood pressure and triglycerides, hyperglycemia represents the strongest risk factor in women.