While proteins found in multiple preparations may not be more important than those found only a single sample, the presence of annexin 2 and integrin β1 in all three samples as well as in a number of other viruses (for example, integrin β1 has also been detected in influenza, HIV-1 and Moloney murine leukemia virus), suggests that these two proteins may be involved in widely used viral processes (see far right column of Table 1 for complete listing and references). Here, ANXA2 is linked to influenza.