Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:In the past decade, ion channels have been demonstrated as crucial players in tumor initiation and progression, since dysregulated expression of as well as mutations in several ion channels genes have been uncovered to influence the malignant phenotypes of cancer cells [2,7].
Category: