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:Overexpression of BCAR3 in the epithelial-like, estrogen receptor-expressing MCF7 breast cancer cells is known to lead to a more mesenchymal and migratory phenotype characterized by the formation of peripheral membrane ruffles and lamellipodia that are rich in filamentous actin and also BCAR1 and BCAR3 (23, 30, 31, 33, 39).
Category: