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:Survival and proliferation of adult ICC is dependent on several factors including Kit, 5HT (serotonin) signaling through the 5HT2B receptor, Ano1, heme oxygenase 1 and neuronal nitric oxide synthase [101].
Category: