Paxillin and p130CAS are two adaptor
proteins localized at the focal adhesions which play an important role in cell signaling, cell motility and oncogenic transformation. In this study we evaluated the levels of
paxillin and p130CAS in feline and canine mammary
tumor tissues at different stages of
malignancy. The results obtained by Western blotting analysis showed no significant differences in the amounts of
paxillin and p130CAS between normal and non-invasive
tumor tissues. By contrast, mammary
tumor tissues with the invasive phenotype showed lower levels of
paxillin P < 0.01 and higher levels of p130CAS P < 0.001 than normal tissues. The decrease P < 0.001 of the amount of
paxillin and the increase P < 0.001 of p130CAS levels were correlated with the progression stage of
malignancy. Since
paxillin and p130CAS are involved in regulating cell migration, our results suggest that low levels of
paxillin together with high levels of p130CAS expression may cause certain breast
cancers to be more motile and possibly more aggressive. Thus, both
paxillin and p130CAS may represent useful prognosticators of feline and canine
breast cancer malignancy.