Integrins are involved in the metastatic cascade and have been found to be responsible for intrinsic and acquired therapy resistance. Therefore, targeting integrins, or more specifically the signal transduction via integrin adhesion complexes (IACs), is a promising therapeutic opportunity to reduce tumor metastasis and overcome therapeutic resistance. Using mass spectrometry–based proteomics, we analysed the components of integrin adhesion complexes of RPMI-7951 cells in long term culture. The adhesome of RPMI-7951 cells contained three integrin receptor subunits: αV, β5 and β1. The most abundant integrin subunits were αV and β5, suggesting that these cells primarily use αVβ5 for adhesion in long term 2D culture. Integrin subunit α5 was detected, but at very low levels, suggesting that these cells may also express α5β1. To determine which proteins were found in αVβ5-containing adhesions, transient knockdown of integrin subunit αV was performed and IAC composition was compared to cells transfected with control siRNA.