As an essential component of the cell skeleton, integrin connects the framework of the cells to the extra-cellular matrix (ECM).
In the process of tumor invasion, as well as other tissue remodeling processes such as embryonic development, the expression and activity of integrin are frequently regulated to direct and facilitate cell migration.
In a range of cancers, it has been reported that integrin overexpression is connected with tumor invasiveness and integrin may serve as a biomarker of malignant transformation.
Here, employing the above designed peptamer and the developed biosensing method, integrin abundance in several clinical samples of thyroid carcinoma is assayed, with the results being grouped, respectively, according to the T (tumor), N (node), and M (distant metastasis) stages of the cases examined (Figure 4).
Under the grouping based on T stage and M stage, the samples show no evident connection with the advancing of cancer (Figure 4a,c), but the expression seems to be, to some extent, correlated with N stage, or the situation of lymphnode metastasis (Figure 4b).
This can be explained considering the biological function of integrin in regulating cell connection withECM.
As a matter of fact,breaking through the tissue barriers such as the ECM and the basal membrane is the necessary step of tumor filtration and metastasis.
In this process, the up-regulation of integrin can indicate a frequent reconfiguration of cellular connection with the ECM, so integrin overexpression can usually be detected on the front edge of invasion, as well as sites of early metastasis located closely to the primary tumor, such as the sentinel lymph nodes.